Transmission management system, transmission system, program, program supply system, and maintenance system

ABSTRACT

A transmission management system that manages image communications among a plurality of transmission terminals capable of performing at least voice communications. The transmission system includes a terminal management section that manages image communications state information indicating an image communications state of each of the transmission terminals for each terminal identification information for identifying each transmission terminal, a creation section that creates a specified communications control message causing the specified transmission terminal to control the image communications in accordance with the image communications state information, and a transmitting section that transmits the created communications control message to the transmission terminal caused to control the image communications.

TECHNICAL FIELD

The present invention relates to an invention for managingcommunications of content data used for having conversations among aplurality of transmission terminals.

BACKGROUND ART

One of the examples of a transmission system that transmits and receivescontent data among a plurality of transmission terminals through arelaying apparatus is a television conference system in which atelevision conference is held though a communications network such asthe Internet. The need for such a television conference system has beenincreasing because of the recent demand for reduction in cost and timetaken for business trips. In such a television conference system, aplurality of television conference terminals, which are examples of thetransmission terminals, are used. A television conference can proceed bytransmitting and receiving image data and voice data among thetelevision conference terminals.

There are inadequate environments for a television conference, such asprivate places including home. As a countermeasure for a televisionconference held under such an environment, a transmission terminal hasbeen developed that acquires a state of the environment under whichanother transmission terminal on the other parties' side is installedand controls image communications or voice communications (refer toJapanese Patent Application Laid-open No. 2008-131412).

The transmission terminal disclosed in Japanese Patent ApplicationLaid-open No. 2008-131412, however, controls the image communications orthe voice communications simply by taking into consideration thesurrounding environment of the transmission terminal on the otherparties' side, but does not control the image communications by takinginto consideration the image communications state of the transmissionterminal on the other parties' side. That is, the transmission terminaldisclosed in Japanese Patent Application Laid-open No. 2008-131412 doesnot control the image communications by taking into consideration theimage communications state, such as the transmission terminal on theother parties' side has a voice communications function but has no imagecommunications function or the transmission terminal on the otherparties' side has an image communications function but is not performingimage communications. Accordingly, when the transmission terminalperforms image communications with the transmission terminal on theother parties' side in the above-described state, the imagecommunications will run to waste because the transmission terminal onthe other parties' side cannot respond to the image communications.

DISCLOSURE OF INVENTION

A transmission management system manages image communications among aplurality of transmission terminals capable of performing at least voicecommunications. The transmission management system includes a terminalmanagement section that manages image communications state informationindicating an image communications state of each of the transmissionterminals for each terminal identification information for identifyingeach transmission terminal, a creation section that creates a specifiedcommunications control message causing the specified transmissionterminal to control the image communications in accordance with theimage communications state information, and a transmitting section thattransmits the created communications control message to the transmissionterminal caused to control the image communications among thetransmission terminals.

According to the aforementioned transmission management system, in afirst case in which the image communications state information indicatesthat a single transmission terminal is performing image communicationsand one or more other transmission terminals are halting imagecommunications among the transmission terminals, the creation sectionmay create a first communications control message indicating that theone or more other transmission terminals are halting imagecommunications and a second communications control message indicatingthat the single transmission terminal is performing imagecommunications, and the transmitting section may transmit the firstcommunications control message to the single transmission terminal thatis performing image communications and the second communications controlmessage to the one or more other transmission terminals that are haltingimage communications.

According to the aforementioned transmission management system, in asecond case in which the image communications state informationindicates that more than one the transmission terminals are performingimage communications and one or more other transmission terminals arehalting image communications among the transmission terminals, thecreation section may create a third communications control messageindicating that the more than one transmission terminals are performingimage communications, and the transmitting section may transmit thethird communications control message to the one or more othertransmission terminals that are halting image communications.

According to the aforementioned transmission management system, in athird case in which the image communications state information indicatesthat a single transmission terminal is performing image communicationsand one or more other transmission terminals have no imagecommunications function among the transmission terminals, the creationsection may create a fourth communications control message indicatingthat the image communications is to be forcibly stopped, and thetransmitting section may transmit the fourth communications controlmessage to the single transmission terminal that is performing imagecommunications.

According to the aforementioned transmission management system, in afourth case in which the image communications state information does notcorrespond to any of the first to the third cases, the creation sectionmay create a display control message indicating that specified displaymessages displayed on the transmission terminals are to be deleted, andthe transmitting section may transmit the display control message to thetransmission terminals.

A transmission system includes the aforementioned transmissionmanagement system and the aforementioned transmission terminals. Each ofthe transmission terminals includes a receiving section that receives acommunications control message transmitted from the transmissionmanagement system, and a display control section that causes a specifieddisplay section to display a display message based on the receivedcommunications control message.

A transmission system includes the aforementioned transmissionmanagement system and the aforementioned transmission terminals. Each ofthe transmission terminals includes a receiving section that receives acommunications control message transmitted from the transmissionmanagement system, and a communications stop section that causes thetransmission terminal to stop performing image communications inaccordance with the received communications control message.

According to the aforementioned transmission system, each of thetransmission terminals may further include a control section that causesan image capturing section imaging a subject and obtaining image data tobe subjected to the image communications to stop the imaging inaccordance with the communications control message received by thereceiving section.

A transmission system includes the aforementioned transmissionmanagement system and the aforementioned transmission terminals. Each ofthe transmission terminals includes a receiving section that receives adisplay control message transmitted from the transmission managementsystem, and a display control section that causes a specified displaysection to delete the specified display message displayed on thespecified display section in accordance with the received displaycontrol message.

A program causes the transmission management system to function as eachof the aforementioned section.

A program supply system supplies the aforementioned program to thetransmission management system through a communications network.

A maintenance system performs maintenance of the aforementionedtransmission management system.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of a transmission system according to a firstembodiment;

FIG. 2 is a conceptual view illustrating a state of transmitting andreceiving of image data, voice data, and various types of managementinformation in the transmission system;

FIGS. 3A to 3C are conceptual views explaining image quality of theimage data;

FIG. 4 is an external view of a terminal according to the embodiment;

FIG. 5 is a schematic illustrating a hardware structure of the terminalaccording to the embodiment;

FIG. 6 is a schematic illustrating a hardware structure of a managementsystem, a relaying apparatus, or a program supply system according tothe embodiment;

FIG. 7 is a functional block diagram of each terminal, each apparatus,and the system included in the transmission system according to theembodiment;

FIG. 8 is a schematic illustrating a functional structure of a finalfiltering section;

FIG. 9 is a schematic illustrating a functional structure of a primaryfiltering section;

FIG. 10 is a conceptual view illustrating a quality change managementtable;

FIG. 11 is a conceptual view illustrating a relaying apparatusmanagement table;

FIG. 12 is a conceptual view illustrating a terminal authenticationmanagement table;

FIG. 13 is a conceptual view illustrating a terminal management table;

FIG. 14 is a conceptual view illustrating a destination list managementtable;

FIG. 15 is a conceptual view illustrating a session management table;

FIG. 16 is a conceptual view illustrating an address priority managementtable;

FIG. 17 is a conceptual view illustrating a transmission speed prioritymanagement table;

FIG. 18 is a conceptual view illustrating a quality management table;

FIG. 19 is a sequence diagram illustrating processing to control stateinformation indicating an operation state of each relaying apparatus;

FIG. 20 is a sequence diagram illustrating processing at a preparatorystage in which a preparation is made for starting remote communicationsbetween terminals;

FIG. 21 is a sequence diagram illustrating filtering processing toselect the relaying apparatuses;

FIG. 22 is a sequence diagram illustrating filtering processing toselect the relaying apparatuses;

FIG. 23 is a schematic illustrating calculated points of priorities whenthe filtering processing to select the relaying apparatuses isperformed;

FIG. 24 is a sequence diagram illustrating processing in which thetransmission terminal selects the relaying apparatus according to thefirst embodiment;

FIG. 25 is a flowchart illustrating processing in which the transmissionterminal selects the relaying apparatus;

FIG. 26 is a sequence diagram illustrating processing to create,transmit and receive a communications control message;

FIG. 27 is a flowchart illustrating processing to mainly create thecommunications control message;

FIG. 28 is a flowchart illustrating a part of processing to create thecommunications control message in detail;

FIG. 29 is a schematic illustrating an example of a televisionconference screen displayed on a display of the transmission terminal;

FIG. 30 is a schematic illustrating an example of the televisionconference screen displayed on the display of the transmission terminal;

FIG. 31 is a schematic illustrating an example of the televisionconference screen displayed on the display of the transmission terminal;

FIG. 32 is a schematic illustrating an example of the televisionconference screen displayed on the display of the transmission terminal;and

FIG. 33 is a sequence diagram illustrating processing in which imagedata and voice data are transmitted and received between the terminals.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

An embodiment is described below with reference to FIGS. 1 to 33. In theembodiment, a transmission terminal performs voice communications bytransmitting voice data to another transmission terminal on the otherparties' side and performs image communications by transmitting imagedata to the transmission terminal on the other parties' side.

<<Overall Structure of Embodiment>>

FIG. 1 is a schematic of a transmission system 1 according to theembodiment. FIG. 2 is a conceptual view illustrating a state oftransmitting and receiving of image data, voice data, and various typesof management information in the transmission system. FIGS. 3A to 3C areconceptual views explaining image quality of the image data.

The transmission system includes a data supply system in which contentdata is transmitted from a transmission terminal on one side to anothertransmission terminal on the other side through a transmissionmanagement system in one direction and a communication system in whichinformation and feelings, for example, are mutually transmitted among aplurality of transmission terminals through the transmission managementsystem. The communication system is a system for transmittinginformation and feelings mutually among a plurality of communicationterminals (corresponding to the “transmission terminals”) through acommunication management system (corresponding to the “transmissionmanagement system”). Examples of the communication system include atelevision conference system and a television telephone system.

In the embodiment, the transmission system, the transmission managementsystem, and the transmission terminal are described on the assumption ofthe television conference system as an example of the communicationsystem, a television conference management system as an example of thecommunication management system, and a television conference terminal asan example of the communication terminal. That is, the transmissionterminal and the transmission management system of the embodiment areapplicable to not only the television conference system but also thecommunication system or a transmission system. The term “televisionconference”, which is described in the embodiment, may be called as a“video conference”. Both are used as the same meaning.

The transmission system 1 illustrated in FIG. 1 includes a plurality oftransmission terminals (10 aa, 10 ab, . . . ), displays (120 aa, 120 ab,. . . ) serving as displays for the respective transmission terminals(10 aa, 10 ab, . . . ), a plurality of relaying apparatuses (30 a, 30 b,30 c, and 30 d), a transmission management system 50, a program supplysystem 90, and a maintenance system 100.

The transmission terminals 10 perform transmission by transmitting andreceiving image data and voice data, which are examples of content data.

Hereinafter, the “transmission terminal” is simply expressed as the“terminal” while the “transmission management system” is simplyexpressed as the “management system”. An arbitrary terminal among theterminals (10 aa, 10 ab, . . . ) is expressed as a “terminal 10”. Anarbitrary display among the displays (120 aa, 120 ab, . . . ) isexpressed as a “display 120”. An arbitrary relaying apparatus among therelaying apparatuses (30 a, 30 b, 30 c, and 30 d) is expressed as a“relaying apparatus 30”. A terminal that requests a start of atelevision conference as a request origin is expressed as a “requestorigin terminal” and another terminal that is a destination of therequest (relay destination) is described as a “destination terminal”.

As illustrated in FIG. 2, in the transmission system 1, a managementinformation session “sei” for transmitting and receiving various typesof management information is established between the request originterminal and the destination terminal through the management system 50.In addition, between the request origin terminal and the destinationterminal, four sessions are established for transmitting and receivingfour pieces of high resolution image data, medium resolution image data,low resolution image data, and voice data through the relaying apparatus30. In the embodiment, the four sessions are collectively described asan image/voice data session sed.

A resolution of an image represented by the image data in the embodimentis described below. The image includes a low resolution image that iscomposed of 160 pixels horizontally and 120 pixels vertically asillustrated in FIG. 3A and serves as a base image, a medium resolutionimage composed of 320 pixels horizontally and 240 pixels vertically asillustrated in FIG. 3B, and a high resolution image composed of 640pixels horizontally and 480 pixels vertically as illustrated in FIG. 3C.Among them, when the image data is transmitted through a narrowbandwidth path, low image quality image data composed of only lowresolution image data serving as the base image is relayed. When thebandwidth is relatively wide, medium image quality image data composedof the low resolution image data serving as the base image and imagedata including medium resolution image data is relayed. When thebandwidth is very wide, high image quality image data including the lowresolution image data serving as the base image, the medium resolutionimage data, and high resolution image data is relayed.

The relaying apparatus 30 illustrated in FIG. 1 relays content dataamong the terminals 10. The management system 50 manages integrally orcollectively a login authentication from the terminal 10, a managementof a telephone conversation state of the terminal 10, a management ofdestination list and the like, as well as a communication state of therelaying apparatus 30. Images represented by the image data may bemoving images or still images, or both moving and still images.

A plurality of routers (70 a, 70 b, 70 c, 70 d, 70 ab, and 70 cd) selectoptimal routes for image data and voice data. Hereinafter, an arbitraryrouter among the routers (70 a, 70 b, 70 c, 70 d, 70 ab, and 70 cd) isexpressed as a “router 70”.

The program supply system 90 includes an HD (Hard Disk) 204, which isdescribed later. A terminal program enabling the terminal 10 to realizevarious functions (or to function as various sections) is stored in theHD 204. The program supply system 90 can transmit the terminal programto the terminal 10. In addition, the program supply system 90 stores arelaying apparatus program enabling the relaying apparatus 30 to realizevarious functions (or to function as various sections) in the HD 204 andcan transmit the relaying apparatus program to the relaying apparatus30. Furthermore, the program supply system 90 stores a transmissionmanagement program enabling the management system 50 to realize variousfunctions (or to function as various sections) in the HD 204 and cantransmit the transmission management program to the management system50.

The maintenance system 100 is a computer that performs maintenancemanagement or maintenance of at least one of the terminal 10, therelaying apparatus 30, the management system 50 and the program supplysystem 90. For example, when the maintenance system 100 is installeddomestically while the terminal 10, the relaying apparatus 30, themanagement system 50 or the program supply system 90 is installedoverseas, the maintenance system 100 remotely performs the maintenancemanagement or the maintenance of at least one of the terminal 10, therelaying apparatus 30, the management system 50 and the program supplysystem 90 through a communications network 2. The maintenance system 100also performs the maintenance, such as the management of a model number,a product serial number, a sale destination, maintenance and inspection,or a failure history, of at least one of the terminal 10, the relayingapparatus 30, the management system 50 and the program supply system 90without using the communications network 2.

The terminals (10 aa, 10 ab, 10 ac, . . . ), the relaying apparatus 30a, and the router 70 a are coupled to each other with a LAN 2 a so as toenable communications among them. The terminals (10 ba, 10 bb, 10 bc, .. . ), the relaying apparatus 30 b, and the router 70 b are coupled toeach other with a LAN 2 b so as to enable communications among them. TheLANs 2 a and 2 b are coupled to each other with a dedicated line tabincluding the router 70 ab so as to enable communications among them,and structured in a predetermined area A. For example, the area A isJapan and the LAN 2 a is structured in a business office in Tokyo whilethe LAN 2 b is structured in a business office in Osaka.

The terminals (10 ca, 10 cb, 10 cc, . . . ), the relaying apparatus 30c, and the router 70 c are coupled to each other with a LAN 2 c so as toenable communications among them. The terminals (10 da, 10 db, 10 dc, .. . ), the relaying apparatus 30 d, and the router 70 d are coupled toeach other with a LAN 2 d so as to enable communications among them. TheLANs 2 c and 2 d are coupled to each other with a dedicated line 2 cdincluding the router 70 cd so as to enable communications among them,and structured in a predetermined area B. For example, the area B is theUnited States of America and the LAN 2 c is structured in a businessoffice in New York while the LAN 2 d is structured in a business officein Washington, D.C. The areas A and B are coupled to each other with therouters (70 ab, 70 cd) through Internet 2 i so as to enablecommunications therebetween.

The management system 50 and the program supply system 90 are coupled toeach terminal 10 and each relaying apparatus 30 via the Internet 2 i soas to enable the systems to perform communications with each terminal 10and each relaying apparatus 30. The management system 50 and the programsupply system 90 may be disposed in the area A or the area B, or in anyarea other than the areas A and B.

In the embodiment, the communications network 2 of the embodiment isstructured with the LANs 2 a and 2 b, the dedicated lines 2 ab and 2 cd,the Internet 2 i, and the LANs 2 c and 2 d. The communications network 2may include a section in which communications is performed wirelesslysuch as Wi-Fi (Wireless Fidelity) or Bluetooth (registered trademark)besides the wired transmission.

In FIG. 1, four numbers indicated under each terminal 10, each relayingapparatus 30, the management system 50, each router 70, and the programsupply system 90 simply represent commonly used IP addresses in IPv4.For example, the IP address of the terminal 10 aa is “1.2.1.3”. The IPv6may be also used instead of IPv4. However, the explanation is made byusing IPv4 for simple explanation.

Each terminal 10 may be used in a telephone conversation made in thesame room, or in a telephone conversation made between an outdoor siteand an indoor site or among the outdoor sites in addition to a telephoneconversation made among a plurality of business offices and a telephoneconversation made among different rooms in the same business office.When each terminal 10 is used at an outdoor site, communications isperformed wirelessly such as a cellular phone communications network.

<<Hardware Structure of Embodiment>>

A hardware structure of the embodiment is described below. FIG. 4 is anexternal view of the terminal 10 according to the embodiment. In thefollowing description, a longitudinal direction of the terminal 10 isdefined as an X-axis direction, a direction orthogonal to the X-axisdirection in a horizontal plane is defined as a Y-axis direction, and adirection perpendicular to the X-axis and Y-axis directions (verticaldirection) is defined as a Z-axis direction.

As illustrated in FIG. 4, the terminal 10 includes a housing 1100, anarm 1200, and a camera housing 1300. A front sidewall surface 1110 ofthe housing 1100 includes an air intake surface (not illustrated) havinga plurality of air intake holes. A rear sidewall surface 1120 of thehousing 1100 includes an air exhaust surface 1121 having a plurality ofair exhaust holes. As a result, external air at the front of theterminal 10 can be taken in through the air intake surface (notillustrated) and the taken air can be exhausted toward the rear of theterminal 10 through the air exhaust surface 1121. A right sidewallsurface 1130 of the housing 1100 has a sound-collecting hole 1131. Thesound-collecting hole 1131 enables a built-in microphone 114, which isdescribed later, to collect sounds such as voices, other sounds, andnoises.

An operation panel 1150 is formed on a side adjacent to the rightsidewall surface 1130 of the housing 1100. The operation panel 1150 isprovided with a plurality of operation buttons (108 a to 108 e), a powersource switch 109, and an alarm lamp 119, which are described later, andincludes a sound output surface 1151 having a plurality of voice outputholes through which output sound from a built-in speaker 115, which isdescribed later, passes. In addition, a housing section 1160 is formedin a recess so as to house the arm 1200 and the camera housing 1300, ona side adjacent to a left sidewall surface 1140 of the housing 1100. Theright sidewall surface 1130 of the housing 1100 is provided with aconnecting ports (1132 a to 1132 c) for electrically connecting cablesto an external device connection I/F 118, which is described later. Onthe other hand, the left sidewall surface 1140 of the housing 1100 isprovided with a connecting port (not illustrated) for electricallyconnecting a cable 120 c for a display 120 to the external deviceconnection I/F 118, which is described later.

In the following description, an arbitrary operation button among theoperation buttons (108 a to 108 e) is expressed as an “operation button108” while an arbitrary connecting port among the connecting ports (1132a to 1132 c) is expressed as a “connecting port 1132”.

The arm 1200 is mounted on the housing 1100 with a torque hinge 1210such that the arm 1200 is rotatable with respect to the housing 1100 inthe up-down direction within a range of a tilt angle θ1 of 135 degrees.FIG. 4 illustrates the state when the tilt angle θ1 is 90 degrees.

The camera housing 1300 includes a built-in camera 112, which isdescribed later. The camera 112 can be used to image a user, a document,and a room, for example. The camera housing 1300 has a torque hinge1310. The camera housing 1300 is mounted on the arm 1200 with the torquehinge 1310. The camera housing 1300 is mounted on the arm 1200 with thetorque hinge 1310 such that the camera housing 1300 is rotatable withrespect to the arm 1200 in the up-down and left-right directions withina range of a pan angle θ2 of ±180 degrees when the angle is 0 degrees inthe state illustrated in FIG. 4 and within a range of a tilt angle θ3 of±45 degrees.

The relaying apparatus 30, the management system 50, and the programsupply system 90 have the same outer appearances as those of typicalservers and computers. The description of their outer appearances isthus omitted.

FIG. 5 is a schematic illustrating a hardware structure of the terminal10 according to the embodiment. As illustrated in FIG. 5, the terminal10 of the embodiment includes a CPU (Central Processing Unit) 101 thatcontrols overall operation of the terminal 10, a ROM (Read Only Memory)102 that stores therein a program used to drive the CPU 101 such as anIPL (Initial Program Loader), a RAM (Random Access Memory) 103 used as aworking area of the CPU 101, a flash memory 104 that stores thereinvarious types of data such as the terminal program, the image data, andthe voice data, and an SSD (Solid State Drive) 105 that controls readingof various types of data, from or writing various types of data into theflash memory 104 under the control of the CPU 101, a media drive 107that controls reading of data from or writing (storing) of data into arecording medium 106 such as a flash memory, the operation buttons 108operated when a destination of the terminal 10 is selected, for example,the power source switch 109 that switches ON and OFF of the power sourceof the terminal 10, and a network I/F (Interface) 111 that performs datatransmission by utilizing the communications network 2.

The terminal 10 further includes the built-in camera 112 that images asubject and acquires the image data under the control of the CPU 101, animage capturing device I/F 113 that controls driving of the camera 112,the built-in microphone 114 that receives voices, the built-in speaker115 that outputs voices, a voice input-output I/F 116 that processesinput and output of a voice signal between the microphone 114 and thespeaker 115 under the control of the CPU 101, a display I/F 117 thattransmits image-data to the display 120 externally mounted under thecontrol of the CPU 101, the external device connection I/F 118 thatconnects various external devices, the alarm lamp 119 that alarms theabnormalities of the various functions of the terminal 10, and a busline 110 that electrically connects the above-described components asillustrated in FIG. 5, such as an address bus or a data bus. Someterminals 10 do not include the cameras 112 and the image capturingdevice I/Fs 113 depending on the models.

The display 120 includes a liquid crystal or organic EL by which imagesof subjects and operation icons, for example, are displayed. The display120 is coupled to the display I/F 117 with the cable 120 c. The cable120 c may be an analog RGB (VGA) signal cable, a component video cable,an HDMI (High-Definition Multimedia Interface) signal cable, or a DVI(Digital Video Interactive) signal cable.

The camera 112 includes a lens and a solid state image capturing devicethat converts light into charges so as to generate an electricallyavailable image (picture) of a subject. As the solid state imagecapturing device, a CMOS (Complementary Metal Oxide Semiconductor) or aCCD (Charge Coupled Device) is used, for example.

The external device connection I/F 118 can be coupled with externaldevices such as an external camera, an external microphone, and anexternal speaker via USB (Universal Serial Bus) cables, for example.When an external camera is coupled, the external camera is driven priorto the built-in camera 112 under the control of the CPU 101. Likewise,when an external microphone and an external speaker are coupled, theexternal microphone and the external speaker are driven prior to thebuilt-in microphone 114 and the built-in speaker 115 under the controlof the CPU 101.

The recording medium 106 is attachable to and detachable from theterminal 10. An EEPROM (Electrically Erasable and Programmable ROM) maybe used, for example, as a non-volatile memory from which data is reador into which data is written under the control of the CPU 101. Thenon-volatile memory is not limited to the flash memory 104.

The terminal program may be recorded into a computer readable recordingmedium such as the recording medium 106 in an installable format or anexecutable format and distributed. The terminal program may be stored inthe ROM 102 instead of the flash memory 104.

FIG. 6 is a schematic illustrating a hardware structure of themanagement system according to the embodiment. The management system 50includes a CPU 201 that controls the overall operation of the managementsystem 50, a ROM 202 that stores therein a program used to drive the CPU201 such as an IPL, a RAM 203 used as a working area of the CPU 201, theHD 204 that stores therein various types of data such as thetransmission management program, an HDD (Hard Disk Drive) 205 thatcontrols reading of various types of data from or writing of varioustypes of data into the HD 204 under the control of the CPU 201, a mediadrive 207 that controls reading data from or writing (storing) data intoa recording medium 206 such as a flash memory, a display 208 thatdisplays various types of information such as a cursor, menus, windows,characters, and images, a network I/F 209 that performs data transfer byutilizing the communications network 2, a keyboard 211 that is providedwith a plurality of keys to input characters, numerical values, andvarious instructions, a mouse 212 that is used to select and executevarious instructions, select items to be processed, and move the cursor,a CD-ROM drive 214 that controls reading of various types of data fromor writing of various types of data into a CD-ROM (Compact Disc ReadOnly Memory) 213 as an example of an attachable-detachable recordingmedium, and a bus line 210 that electrically connects theabove-described elements as illustrated in FIG. 6, such as an addressbus or a data bus.

The transmission management program may be recorded into a computerreadable recording medium such as the recording medium 206 or the CD-ROM213 in an installable format or an executable format and distributed.The transmission management program may be stored in the ROM 202 insteadof the HD 204.

The relaying apparatus 30 has the same hardware structure as that of themanagement system 50. The description thereof is thus omitted. However,the HD 204 records the relaying apparatus program that controls therelaying apparatus 30. Also in this case, the relaying apparatus programmay be recorded into a computer readable recording medium such as therecording medium 206 or the CD-ROM 213 in an installable format or anexecutable format and distributed. The relaying apparatus program may bestored in the ROM 202 instead of the HD 204.

The program supply system 90 and the maintenance system 100 have thesame hardware structure as that of the management system 50. Thedescription thereof is thus omitted. The HD 204 records a program supplyprogram that controls the program supply system 90. Also in this case,the program supply program may be recorded into a computer readablerecording medium such as the recording medium 206 or the CD-ROM 213 inan installable format or an executable format and distributed. Theprogram supply system program may be stored in the ROM 202 instead ofthe HD 204.

The programs may be recorded into a computer readable recording mediumsuch as a CD-R (computer Disc recordable), a DVD (digital VersatileDisk), or a Blue-ray disc as another example of the above-describedattachable-detachable recording medium, and supplied.

<<Functional Structure of Embodiment>>

A functional structure of the embodiment is described below. In theembodiment, a case is described in which a delay occurs in receiving ofimage data performed by the terminal 10 serving as a destination (relaydestination), the resolution of an image represented by image data ischanged by the relaying apparatus 30, and thereafter the resulting imagedata is transmitted to the terminal 10 serving as the relay destination.

FIG. 7 is a functional block diagram of each terminal, each apparatus,and the system included in the transmission system 1 of the embodiment.In FIG. 7, the terminal 10, the relaying apparatus 30, and themanagement system 50 are coupled so as to enable data communicationsamong them through the communications network 2. The program supplysystem 90 illustrated in FIG. 1 is omitted in FIG. 7 because the programsupply system 90 does not directly relate to communications in atelevision conference.

<Functional Structure of Terminal>

The terminal 10 includes a transmitting-receiving section 11, anoperation input reception section 12, a login request section 13, animage capturing section 14, a voice input section 15 a, a voice outputsection 15 b, a final filtering section 16, a display control section17, a delay detection section 18, a storage-read processing section 19,and a message creation section 20. Each of the sections is a functionthat is achieved when any of the components illustrated in FIG. 5 areoperated by commands from the CPU 101 in accordance with the terminalprogram loaded on the RAM 103 from the flash memory 104, or means forperforming the function. The terminal 10 includes a storage section 1000structured by the RAM 103 and the flash memory 104 that are illustratedin FIG. 5.

(Functional Structures of Terminal)

Each functional structure of the terminal 10 is described in detail withreference to FIGS. 5 and 7. In the following description of eachfunctional structure of the terminal 10, a relationship between eachfunctional structure of the terminal 10 and major components thatachieve each functional structure among the components illustrated inFIG. 5 is also described.

The transmitting-receiving section 11 of the terminal 10 illustrated inFIG. 7 is achieved by a command from the CPU 101 illustrated in FIG. 5and the network I/F 111 illustrated in FIG. 5. Thetransmitting-receiving section 11 transmits and receives various typesof data (or information) between itself and the other terminals,apparatuses, or the system through the communications network 2. Thetransmitting-receiving section 11 starts receiving pieces of stateinformation indicating the states of the respective terminals serving asdestination candidates from the management system 50 before starting atelephone conversation with a desired destination terminal. The stateinformation indicates not only the operation state of each terminal 10(an online state or an offline state) but also a detailed state such aswhether in the online state and a telephone conversation can be made,whether in a busy state, or whether a user is absent. In addition, thestate information indicates not only the operation state of the terminal10 but also various states in the terminal 10. For example, a state inwhich the cable 120 c is come off from the terminal 10, a state in whichthe terminal 10 outputs voices but no images, and a state in which theterminal 10 outputs no voices (MUTE). A case in which the stateinformation indicates the operation state is described below as anexample.

The operation input reception section 12, which is achieved by a commandfrom the CPU 101 illustrated in FIG. 5, and the operation buttons 108and the power source switch 109 illustrated in FIG. 5, receives varioustypes of inputs from a user. For example, once a user turns ON the powersource switch 109 illustrated in FIG. 5, the operation input receptionsection 12 illustrated in FIG. 7 receives the power source ON and causesthe power source to be turned ON.

The login request section 13, which is achieved by a command from theCPU 101 illustrated in FIG. 5, once the power source ON is received,automatically transmits login request information indicating a requestfor a login and a current IP address of the request origin terminal tothe management system 50 from the transmitting-receiving section 11through the communications network 2. When the user switches the powersource switch 109 from the ON state to the OFF state, the operationinput reception section 12 completely turns OFF the power source afterthe transmitting-receiving section 11 transmits the state informationindicating that the power source is to be turned OFF to the managementsystem 50. As a result, the management system 50 can grasp the fact thatthe power source of the terminal 10 has been turned OFF from the ONstate.

The image capturing section 14, which is achieved by a command from theCPU 101 illustrated in FIG. 5, and the camera 112 and the imagecapturing device I/F 113 illustrated in FIG. 5, images a subject andoutputs the resulting image data. Some terminals 10 do not include theimage capturing sections 14 depending on the models.

The voice input section 15 a, which is achieved by a command from theCPU 101 illustrated in FIG. 5 and the voice input-output I/F 116illustrated in FIG. 5, inputs voice data relating to a voice signal,after the microphone 114 converts a voice of a user into the voicesignal. The voice output section 15 b, which is achieved by a commandfrom the CPU 101 illustrated in FIG. 5 and the voice input-output I/F116 illustrated in FIG. 5, outputs a voice signal relating to voice datato a speaker so as to cause the speaker 115 to output a voice.

The final filtering section 16 is achieved by a command from the CPU 101illustrated in FIG. 5 so as to include a measurement section 16 a, acalculation section 16 b, and a final selection section 16 c asillustrated in FIG. 8. The final filtering section 16 performs finalfiltering processing in which one of the relaying apparatuses 30 isfinally selected.

The measurement section 16 a measures a receiving date at which thetransmitting-receiving section 11 receives prior transmissioninformation, which is described later, for each prior transmissioninformation received by the transmitting-receiving section 11. Thecalculation section 16 b calculates a necessary period of time (T) fromtransmitting to receiving the prior transmission information inaccordance with a difference between the measured receiving time and atransmission date included in the prior transmission information foreach prior transmission information for which the measurement section 16a has measured the receiving date. The final selection section 16 cfinally selects one of the relaying apparatuses by selecting therelaying apparatus 30 that has relayed the prior transmissioninformation having the shortest necessary period of time among thenecessary periods of time calculated by the calculation section 16 b.

The display control section 17, which is achieved by a command from theCPU 101 illustrated in FIG. 5 and the display I/F 117 illustrated inFIG. 5, performs control so as to combine received pieces of image datahaving different resolutions and transmit the combined image data to thedisplay 120, which is described later. The display control section 17can transmit information indicating a destination list received from themanagement system 50 to the display 120 so as to cause the display 120to display the destination list. In addition, the display controlsection 17 causes the display 120 to display the screens illustrated inFIGS. 29 to 32. The screens illustrated in FIGS. 29 to 32 are describedlater.

The delay detection section 18, which is achieved by a command from theCPU 101 illustrated in FIG. 5, detects delay time (ms) of image data orvoice data transmitted from the other terminals 10 through the relayingapparatus 30.

The storage-read processing section 19, which is executed by a commandfrom the CPU 101 illustrated in FIG. 5 and the SSD 105 illustrated inFIG. 5 or achieved by a command from the CPU 101, stores various typesof data in the storage section 1000 or reads various types of datastored in the storage section 1000. The storage section 1000 storestherein a terminal ID (Identification) and a password for identifyingthe terminal 10, for example.

The message creation section 20, which is achieved by a command from theCPU 101 illustrated in FIG. 5, reads preliminarily stored imagecommunications state information from the storage section 1000 andcreates an image communications state message (m) including the imagecommunications state information. The image communications stateinformation and the image communications state message (m) are describedlater.

The storage section 1000 stores therein the image communications stateinformation, which is described later. In the storage section 1000,image data and voice data that are received when a telephoneconversation is made with the destination terminal are stored andoverwritten with new image data and voice data at every receiving of thedata. In this regard, an image is displayed on the display 120 inaccordance with the image data before being overwritten while a voice isoutput from the speaker 115 in accordance with the voice data beforebeing overwritten.

The terminal ID and a relaying apparatus ID, which is described later,of the embodiment indicate identification information used for uniquelyidentifying the terminal 10 and the relaying apparatus 30. For example,the identification information is languages, characters, symbols, orvarious signs. The terminal ID and the relaying apparatus ID may be theidentification information obtained by combining at least two of thelanguages, characters, symbols, and various signs.

<Functional Structure of Relaying Apparatus>

The relaying apparatus 30 includes a transmitting-receiving section 31,a state detection section 32, a data quality confirmation section 33, aquality change management section 34, a data quality change section 35,and a storage-read processing section 39. Each of the sections is afunction that is achieved when any of the components illustrated in FIG.6 are operated by commands from the CPU 201 in accordance with therelaying apparatus program loaded on the RAM 203 from the HD 204, ormeans for performing the function. The relaying apparatus 30 includes astorage section 3000 structured by the RAM 203 illustrated in FIG. 6and/or the HD 204 illustrated in FIG. 6. FIG. 10 is a conceptual viewillustrating a quality change management table.

(Quality Change Management Table)

In the storage section 3000, a quality change management DB (Date Base)3001 having a quality change management table illustrated in FIG. 10 isstructured. In the quality change management table, the IP address ofthe terminal 10 serving as the relay destination (destination) of imagedata and image quality of the image data to be relayed by the relayingapparatus 30 to the relay destination are managed in association witheach other.

(Functional Structures of Relaying Apparatus)

Next, each functional structure of the relaying apparatus 30 isdescribed in detail. In the following description of each functionalstructure of the relaying apparatus 30, a relationship between eachfunctional structure of the relaying apparatus 30 and major componentsthat achieve each functional structure of the relaying apparatus 30among the components illustrated in FIG. 6 is also described.

The transmitting-receiving section 31 of the relaying apparatus 30illustrated in FIG. 7 is achieved by a command from the CPU 201illustrated in FIG. 6 and the network I/F 209 illustrated in FIG. 6. Thetransmitting-receiving section 31 transmits and receives various typesof data (or information) between itself and the other terminals,apparatuses, or the system through the communications network 2.

The state detection section 32, which is achieved by a command from theCPU 201 illustrated in FIG. 6, detects the operation state of therelaying apparatus 30 including the state detection section 32. Theoperation state is the “online” state, the “offline” state, the “busy”state, or a “temporary halted” state.

The data quality confirmation section 33, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6, searches the quality changemanagement DB 3001 (refer to FIG. 10) by using the IP address of thedestination terminal as a searching key, and extracts image quality ofthe image data to be relayed corresponding to the IP address, therebyconfirming the image quality of the image data to be relayed.

The quality change management section 34, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6, changes the content of thequality change management DB 3001 in accordance with qualityinformation, which is described later, transmitted from the managementsystem 50.

For example, during a television conference held between the requestorigin terminal (terminal 10 aa) having the terminal ID of “01aa” andthe destination terminal (terminal 10 db) having the terminal ID of“01db” by transmitting and receiving high image quality image data, whena delay occurs in receiving the image data in the destination terminal(terminal 10 db) due to a start of another television conference heldbetween the request origin terminal (terminal 10 bb) and the destinationterminal (terminal 10 ca) through the communications network 2, forexample, the relaying apparatus 30 lowers the image quality of the imagedata, which has been relayed by the relaying apparatus 30, from highimage quality to medium image quality. In such a case, the content ofthe quality change management DB 3001 is changed in accordance with thequality information indicating the medium quality so as to lower theimage quality of the image data relayed by the relaying apparatus 30from high quality to medium quality.

The data quality change section 35, which is achieved by a command fromthe CPU 201 illustrated in FIG. 6, changes the image quality of theimage data transmitted from the transmission origin terminal inaccordance with the changed content of the quality change management DB3001.

The storage-read processing section 39, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6 and the HDD 205 illustrated inFIG. 6, stores various types of data in the storage section 3000 orreads various types of data stored in the storage section 3000.

<Functional Structure of Management System>

The management system 50 includes a transmitting-receiving section 51, aterminal authentication section 52, a state management section 53, aterminal extraction section 54, a terminal state extraction section 55,a primary filtering section 56, a session management section 57, aquality determination section 58, a storage-read processing section 59,a delay time management section 60, and a message creation section 61.Each of the sections is a function that is achieved when any of thecomponents illustrated in FIG. 6 are operated by commands from the CPU201 in accordance with the management system program loaded on the RAM203 from the HD 204, or means for performing the function. Themanagement system 50 includes a storage section 5000 structured by theHD 204 illustrated in FIG. 6.

FIG. 8 is a schematic illustrating a functional structure of the finalfiltering section. FIG. 9 is a schematic illustrating a functionalstructure of the primary filtering section. FIG. 11 is a conceptual viewillustrating a relaying apparatus management table. FIG. 12 is aconceptual view illustrating a terminal authentication management table.FIG. 13 is a conceptual view illustrating a terminal management table.FIG. 14 is a conceptual view illustrating a destination list managementtable. FIG. 15 is a conceptual view illustrating a session managementtable. FIG. 16 is a conceptual view illustrating an address prioritymanagement table. FIG. 17 is a conceptual view illustrating atransmission speed priority management table. FIG. 18 is a conceptualview illustrating a quality management table.

(Relaying Apparatus Management Table)

In the storage section 5000, a relaying apparatus management DB 5001having the relaying apparatus management table illustrated in FIG. 11 isstructured. In the relaying apparatus management table, the operationstate of the relaying apparatus 30, a receiving date at which themanagement system 50 received the state information indicating theoperation state, the IP address of the relaying apparatus 30, and amaximum data transmission speed (Mbps) of the relaying apparatus 30 aremanaged in association with each other for each relaying apparatus ID ofthe relaying apparatuses 30. For example, the relaying apparatusmanagement table illustrated in FIG. 11 indicates that, in relation tothe relaying apparatus 30 a having the relaying apparatus ID of “111a”,the operation state is “online”, the date at which the management system50 received the state information is “13:00 on Nov. 10, 2009”, the IPaddress is “1.2.1.2”, and the maximum data transmission speed is 100Mbps.

(Terminal Authentication Management Table)

In addition, in the storage section 5000, a terminal authenticationmanagement DB 5002 having the terminal authentication management tableillustrated in FIG. 12 is structured. In the terminal authenticationmanagement table, the passwords are managed in association with therespective terminal IDs of all of the terminals 10 managed by themanagement system 50. For example, the terminal authenticationmanagement table illustrated in FIG. 12 indicates that the terminal IDof the terminal 10 aa is “01aa” and the password of the terminal 10 aais “aaaa”.

(Terminal Management Table)

Furthermore, in the storage section 5000, a terminal management DB 5003having the terminal management table illustrated in FIG. 13 isstructured. In the terminal management table, for each terminal ID ofthe terminals 10, the destination name of the terminal 10 whendesignated as the destination, the operation state of the terminal 10,an image communications state, which is described later, of the terminal10, a receiving date at which the management system 50 received loginrequest information, which is described later, and the IP address of theterminal 10 are managed in association with each other. For example, theterminal management table illustrated in FIG. 13 indicates that, inrelation to the terminal 10 aa having the terminal ID of “01aa”, thedestination name (terminal name) is “AA terminal, Tokyo business office,Japan”, the operation state is “online (a telephone conversation isenabled)”, the image communications state is “ON”, the date at whichmanagement system 50 received the login request information is “13:40 onNov. 10, 2009”, and the IP address is “1.2.1.3”.

The image communications state information is described below. The imagecommunications state information indicates the state relating to imagecommunications of the terminal 10 as the following four patterns.

ON: a state in which the terminal 10 is performing image communications.

OFF: a state in which the terminal 10 is halting image communications(the terminal 10, however, includes an image communications function forperforming image communications as the image capturing section 14).

NA: a state in which the terminal 10 includes no image communicationsfunction (the terminal 10 includes no image communications function forperforming image communications, which is performed by the imagecapturing section 14).

DC: a state in which the image communications state is unclear (no imagecommunications state is transmitted from the terminal 10 because theterminal 10 is offline or in an initial state).

The storage section 1000 stores therein the image communications stateinformation indicating DC as the default. The image capturing section 14overwrites the image communications state information indicating DC withthe image communications state information indicating ON or OFF. Theimage communications state information indicating NA is stored in thestorage section 1000 as the factory default of the terminal 10.

(Destination List Management Table)

Furthermore, in the storage section 5000, a destination list managementDB 5004 having the destination list management table illustrated in FIG.14 is structured. In the destination list management table, the terminalID of the request origin terminal that requests a start of a telephoneconversation in a television conference and all of the terminal IDs ofthe destination terminals registered as the candidates of thedestination terminal are managed in association with each other. Forexample, the destination list management table illustrated in FIG. 14indicates that the candidates of the destination terminal (terminal 10db) to which the request origin terminal (terminal 10 aa) having theterminal ID of “01aa” can request a start of a telephone conversation ina television conference are the terminal 10 ab having the terminal ID of“01ab”, the terminal 10 ba having the terminal ID of “01ba”, and theterminal 10 bb having the terminal ID of “01bb”. The candidate of thedestination terminal is updated by being added or deleted in response tothe request for adding or deleting the candidate made from any requestorigin terminal to the management system 50.

(Session Management Table)

Furthermore in the storage section 5000, a session management DB 5005having the session management table illustrated in FIG. 15 isstructured. In the session management table, for each selection sessionID used for executing a session for selecting the relaying apparatus 30,the relaying apparatus ID of the relaying apparatus 30 used for relayingimage data and voice data, the terminal ID of the request originterminal, the terminal ID of the destination terminal, delay time (ms)in receiving the image data by the destination terminal, and thereceiving date at which the management system 50 received the delayinformation indicating the delay time from the destination terminal aremanaged in association with each other. For example, the sessionmanagement table illustrated in FIG. 15 indicates that, in relation tothe relaying apparatus 30 a (the relaying apparatus ID is “111a”)selected in a session executed by using a selection session ID “se1”,image data and voice data are relayed between the request originterminal (terminal 10 aa) having the terminal ID of “01aa” and thedestination terminal (terminal 10 db) having the terminal ID of “01db”,and the delay time of the image data is 200 (ms) at the destinationterminal (terminal 10 db) as at “14:00 on Nov. 10, 2009”. When atelevision conference is held between two terminals 10, the receivingdate of the delay information may be managed in accordance with thedelay information transmitted from the request origin terminal, insteadof the destination terminal. However, when a television conference isheld among three or more terminals 10, the receiving date of the delayinformation is managed in accordance with the delay informationtransmitted from the terminal 10 that receives image data and voicedata.

(Address Priority Management Table)

In addition, in the storage section 5000, a priority management DB 5006having the address priority management table illustrated in FIG. 16 isstructured. In the address priority management table, a discrepancy indot addresses and an address priority are managed in association witheach other. The dot address is composed of four section numbers as thecommonly used IP address in IPv4. The more the “same” number is includedin the dot addresses of the terminal 10 and the relaying apparatus 30 atthe corresponding sections in the dot addresses, the higher point theaddress priority has. The term “same” means that the numbers at thecorresponding sections in both dot addresses are equal to each otherwhile the term “difference” means that the numbers at the correspondingsections in both dot addresses are different from each other. Forexample, in the address priority management table illustrated in FIG.16, an IP address has the priority “5” (5 points), when three numericalvalues from the left-most section to the right-most section of a dotaddress are equal to each other between two IP addresses. Similarly, anIP address has the priority “3” (3 points), when two numerical valuesfrom the left-most section to the right-most section of a dot addressare equal to each other between two IP address. In this case, thepriority is independent of whether the numerical value of the right-mostsection of a dot address is the same between two IP address. An IPaddress has the priority “1” (1 point), when the numerical value of theleft-most section is the same but the numerical value of the secondleft-most section of a dot address is not the same between two IPaddresses. In this case, the priority is independent of whether thenumerical value of the right-most section and the numerical value of thesecond right-most section of a dot address are the same between two IPaddress. An IP address has the priority “0” (0 point), when thenumerical value of the left-most section of a dot address is differentbetween two IP addresses. In this case, the priority is independent ofwhether the values from the second left-most section to the right-mostsection of a dot address are the same between two IP addresses.

(Transmission Speed Priority Management Table)

The priority management DB 5006 structured in the storage section 5000also includes the transmission speed priority management tableillustrated in FIG. 17. In the transmission speed priority managementtable, the maximum data transmission speed and a transmission speedpriority are managed in association with each other such that as thevalue of the maximum data transmission speed (Mbps) at the relayingapparatus 30 increases, the higher point the transmission speed priorityhas. For example, in the transmission speed priority management tableillustrated in FIG. 17, when the maximum data transmission speed at therelaying apparatus 30 is 1000 Mbps or more, the point of thetransmission speed priority is “5”. When the maximum data transmissionspeed at the relaying apparatus 30 is 100 Mbps or more and less than1000 Mbps, the point of the transmission speed priority is “3”. When themaximum data transmission speed at the relaying apparatus 30 is 10 Mbpsor more and less than 100 Mbps, the point of the transmission speedpriority is “1”. When the maximum data transmission speed at therelaying apparatus 30 is less than 10 Mbps, the point of thetransmission speed priority is “0”.

(Quality Management Table)

In addition, in the storage section 5000, a quality management DB 5007having the quality management table illustrated in FIG. 18 isstructured. In the quality management table, the delay time (ms) ofimage data and image quality (quality of an image) of image data aremanaged in association with each other such that as the delay time ofimage data at the request origin terminal or the destination terminalincreases, the image quality of image data relayed by the relayingapparatus 30 is lowered.

(Functional Structures of Management System)

Next, each functional structure of the management system 50 is describedin detail. In the following description of each functional structure ofthe management system 50, a relationship between each functionalstructure of the management system 50 and major components that achieveeach functional structure of the management system 50 among thecomponents illustrated in FIG. 6 is also described.

The transmitting-receiving section 51 is executed by a command from theCPU 201 illustrated in FIG. 6 and the network I/F 209 illustrated inFIG. 6. The transmitting-receiving section 51 transmits and receivesvarious types of data (or information) between itself and the otherterminals, apparatuses, or the system through the communications network2.

The terminal authentication section 52, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6, searches the terminalauthentication management DB 5002 of the storage section 5000 by usingthe terminal ID and the password that are included in the login requestinformation received through the transmitting-receiving section 51 assearching keys, and performs terminal authentication by determiningwhether the same terminal ID and password are managed in the terminalauthentication management DB 5002.

The state management section 53, which is achieved by a command from theCPU 201 illustrated in FIG. 6, stores the terminal ID of the requestorigin terminal, the operation state of the request origin terminal, thereceiving date at which the management system 50 received the loginrequest information, and the IP address of the request origin terminalin the terminal management DB 5003 (refer to FIG. 13) and manages themin association with each other so as to manage the operation state ofthe request origin terminal that makes a login request. The statemanagement section 53 changes the operation state in the terminalmanagement DB 5003 (refer to FIG. 13) from online to offline inaccordance with the state information that is sent from the terminal 10and indicates that the power source is to be turned OFF when a userturns OFF the power source switch 109 of the terminal 10 from the ONstate.

The terminal extraction section 54, which is achieved by a command fromthe CPU 201 illustrated in FIG. 6, searches the destination listmanagement DB 5004 (refer to FIG. 14) by using the terminal ID of therequest origin terminal that has made a login request as a key, readsthe terminal IDs of the candidates of the destination terminal capableof having a telephone conversation with the request origin terminal, andextracts the terminal IDs. In addition, the terminal extraction section54 searches the destination list management DB 5004 (refer to FIG. 14)by using the terminal ID of the request origin terminal that has madethe login request as a key, and extracts the terminal IDs of the otherrequest origin terminals that register the terminal ID of the requestorigin terminal as the candidate of the destination terminal.

Furthermore, the terminal extraction section 54 searches the destinationlist management DB 5004 by using the terminal ID of the terminal thathas transmitted the image communications state message (m) as theterminal ID of the request origin terminal, and extracts all of theterminal IDs of the destination terminals corresponding to the terminalID of the terminal that has transmitted the image communications statemessage (m).

The terminal state extraction section 55, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6, searches the terminal managementDB 5003 (refer to FIG. 13) by using the terminal IDs of the candidatesof the destination terminal extracted by the terminal extraction section54 as searching keys, and reads the operation state of each terminal IDextracted by the terminal extraction section 54. As a result, theterminal state extraction section 55 can acquire the operation states ofthe candidates of the destination terminal capable of having a telephoneconversation with the request origin terminal that has made the loginrequest. Furthermore, the terminal state extraction section 55 searchesthe terminal management DB 5003 by using the terminal IDs extracted bythe terminal extraction section 54 as searching keys, and acquires theoperation state of the request origin terminal that has made the loginrequest.

Furthermore the terminal state extraction section 55 searches theterminal management DB 5003 (refer to FIG. 13) by using the terminal IDof the destination terminal as a searching key, and extracts the imagecommunications state information corresponding to that terminal ID. Theterminal state extraction section 55 refers to the terminal managementDB 5003 (refer to FIG. 13) and extracts the IP address of the terminal10 that is in the image communications state, the terminal 10 that ishalting image communications, or the terminal 10 having the imagecommunications function.

The primary filtering section 56, which is achieved by a command fromthe CPU 201 illustrated in FIG. 6, performs primary filtering processingprior to the final filtering processing so as to assist the finalfiltering processing in which one of the relaying apparatuses 30 isfinally selected. The primary filtering section 56 is achieved by acommand from the CPU 201 illustrated in FIG. 5 so as to include aselection session ID generation section 56 a, a terminal IP addressextraction section 56 b, a primary selection section 56 c, and apriority determination section 56 d as illustrated in FIG. 9.

The selection session ID generation section 56 a generates the selectionsession ID used for executing a session for selecting the relayingapparatus 30. The terminal IP address extraction section 56 b searchesthe terminal management DB 5003 (refer to FIG. 13) in accordance withthe terminal ID of the request origin terminal and the terminal ID ofthe destination terminal that are included in start request informationtransmitted from the request origin terminal, and extracts the IPaddresses of the respective terminals 10 corresponding to the terminalIDs. The primary selection section 56 c selects the relaying apparatuses30 by selecting the relaying apparatus IDs of the relaying apparatuses30 the operation state of which are “online” among the relayingapparatuses 30 managed by the relaying apparatus management DB 5001(refer to FIG. 11).

In addition, the primary selection section 56 c searches the relayingapparatus management DB 5001 (refer to FIG. 11) in accordance with theIP addresses of the request origin terminal and the destination terminalthat are extracted by the terminal IP address extraction section 56 b,and investigates whether the dot address of each IP address of therequest origin terminal and the destination terminal is the same as ordifferent from the dot addresses of the IP addresses of the selectedrelaying apparatuses 30. Thereafter, the primary selection section 56 cselects two relaying apparatuses 30 having the top two high totalpoints. The total point is obtained as a sum of the higher point in theaddress priority with respect to the terminals 10 and the point of thetransmission speed priority for each relaying apparatus. Although thetwo relaying apparatuses 30 having the top two high points are selectedin the embodiment, the number of relaying apparatuses 30 to be selectedis not limited to two. Three or more relaying apparatuses 30 having thetop three or more high points may be selected as long as the relayingapparatuses 30 having high points can be selected as many as possible.

The priority determination section 56 d determines the point of theaddress priority for each relaying apparatus 30 investigated by theprimary selection section 56 c with reference to the priority managementDB 5006 (refer to FIG. 16). In addition, the priority determinationsection 56 d searches the priority management DB 5006 (refer to FIG. 17)in accordance with the maximum data transmission speed of each relayingapparatus 30 managed by the relaying apparatus management DB 5001 (referto FIG. 11), and determines the point of the transmission speed priorityof each relaying apparatus 30 selected by the primary filteringprocessing performed by the primary selection section 56 c.

The session management section 57, which is achieved by a command fromthe CPU 201 illustrated in FIG. 6, stores the selection session IDgenerated by the selection session ID generation section 56 a, terminalID of the request origin terminal, and the terminal ID of thedestination terminal in the session management DB 5005 of the storagesection 5000 (refer to FIG. 15), and manages them in association witheach other. In addition, the session management section 57 stores therelaying apparatus ID of the relaying apparatus 30 finally selected bythe final selection section 16 c of the terminal 10 for each selectionsession ID in the session management DB 5005 (refer to FIG. 15), andmanages them.

The quality determination section 58 searches the quality management DB5007 (refer to FIG. 18) by using the delay time as a searching key,extracts the image quality of the image data corresponding to the delaytime, and determines the image quality of the image data to be relayedby the relaying apparatus 30.

The storage-read processing section 59, which is executed by a commandfrom the CPU 201 illustrated in FIG. 6 and the HDD 205 illustrated inFIG. 6, stores various types of data in the storage section 5000 orreads various types of data stored in the storage section 5000.

The delay time management section 60, which is achieved by a commandfrom the CPU 201 illustrated in FIG. 6, searches the terminal managementDB 5003 (refer to FIG. 13) by using the IP address of the destinationterminal as a searching key, and extracts the terminal ID correspondingto the IP address. In addition, the delay time management section 60stores the delay time indicated in the delay information in a field ofthe delay time of a record including the extracted terminal ID in thesession management table of the session management DB 5005 (refer toFIG. 15) and manages the stored delay time.

The message creation section 61 creates a communications control messagein accordance with the image communications state of each terminal 30.Processing to create the communications control message is describedlater in detail with reference to FIG. 28. In addition, the messagecreation section 61 acquires the image communications state informationrelating to the terminal 10 serving as the transmission origin and theIP address of the terminal 10 from the image communications statemessage (m) transmitted from the terminal 10. Furthermore, the messagecreation section 61 rewrites the attribute of the image communicationsstate corresponding to the IP address acquired from the imagecommunications state message (m) in the terminal management DB 5003(refer to FIG. 13) by overwriting it with the image communications stateinformation acquired from the image communications state message (m).

The message creation section 61 extracts, from the terminal managementDB 5003 (refer to FIG. 13), the terminal ID corresponding to the IPaddress acquired from the image communications state message (m).Furthermore, the message creation section 61 determines whether each ofthe request origin terminal and all of the destination terminals has theimage communications function with reference to the image communicationsstate information extracted from the terminal management DB 5003 (referto FIG. 13).

<<Processing or Operation of Embodiment>>

A processing method of the transmission system 1 according to theembodiment is described below with reference to FIGS. 19 to 33. FIG. 19is a sequence diagram illustrating processing to manage stateinformation that indicates a state of each relaying apparatus 30 and istransmitted to the management system 50 from each relaying apparatus 30.FIG. 20 is a sequence diagram illustrating processing at a preparatorystage in which a preparation is made for starting a telephoneconversation among the terminals 10. FIG. 21 is a sequence diagramillustrating filtering processing to select the relaying apparatuses 30.FIG. 22 is a flowchart illustrating filtering processing to select therelaying apparatuses 30. FIG. 23 is a schematic illustrating calculationof the points of priorities when the filtering processing to select therelaying apparatuses 30 is performed. FIG. 24 is a sequence diagramillustrating processing in which the terminal 10 selects the relayingapparatus 30. FIG. 25 is a flowchart illustrating processing in whichthe terminal selects the relaying apparatus 30. FIG. 33 is a sequencediagram illustrating processing in which image data and voice data aretransmitted and received between the terminals.

First, the processing to manage the state information that indicates astate of each relaying apparatus 30 and is transmitted to the managementsystem 50 from each relaying apparatus 30 is described. In each relayingapparatus 30, the state detection section 32 illustrated in FIG. 7periodically detects the operation state of the relaying apparatusitself (steps S1-1 to S1-4). The transmitting-receiving section 31 ofeach relaying apparatus 30 periodically transmits the state informationto the management system 50 through the communications network 2 suchthat the management system 50 manages the operation state of eachrelaying apparatus 30 in real time (steps S2-1 to S2-4). Each stateinformation includes the relaying apparatus ID and the operation sate,which is detected by the state detection section 32, of the relayingapparatus 30 identified with the relaying apparatus ID. In theembodiment, the relaying apparatuses (30 a, 30 b, and 30 d) are in“online” while being normally operated. On the other hand, the relayingapparatus 30 c is “offline” though being operated because some sort offailures have occurred in a program for executing relaying operation ofthe relaying apparatus 30 c.

In the management system 50, the transmitting-receiving section 51receives the state information transmitted from each relaying apparatus30. The management system 50 stores the state information for eachrelaying apparatus ID in the relaying apparatus management DB 5001(refer to FIG. 11) of the storage section 5000 through the storage-readprocessing section 59 and manages them (steps S3-1 to S3-4). As aresult, the operation state is stored for each relaying apparatus ID asany one of “online”, “offline”, and “in failure” in the relayingapparatus management table as illustrated in FIG. 11 and managed.Meanwhile, the receiving date at which the management system 50 receivedthe state information is stored for each relaying apparatus ID andmanaged. When no state information is transmitted from the relayingapparatus 30, fields of the operation state and the receiving date ineach record of the relaying apparatus management table illustrated inFIG. 11 are blank or the operation state and the receiving date of thelatest receiving are indicated in the respective fields.

Transmitting-receiving processing of various types of managementinformation at the preparatory state before a telephone conversationstarts between the terminals 10 aa and 10 db is described below withreference to FIG. 20. In FIG. 20, various types of managementinformation are transmitted and received by the management informationsession “sei” illustrated in FIG. 2.

Once a user turns ON the power source switch 109 illustrated in FIG. 5,the operation input reception section 12 illustrated in FIG. 7 receivesthe power source ON and causes the power source to be turned ON (stepS21). The login request section 13, once the power source ON isreceived, automatically transmits the login request informationindicating a request for a login to the management system 50 from thetransmitting-receiving section 11 through the communications network 2(step S22). The login request information includes the terminal ID andthe password to identify the terminal 10 aa itself serving as a loginrequest origin. The terminal ID and the password are read from thestorage section 1000 through the storage-read processing section 19 andtransmitted to the transmitting-receiving section 11 as data. When thelogin request information is transmitted to the management system 50from the terminal 10 aa, the management system 50 serving as thereceiving side can grasp the IP address of the terminal 10 ab serving asthe transmission side.

Then, the terminal authentication section 52 of the management system 50searches the terminal authentication management DB 5002 of the storagesection 5000 (refer to FIG. 12) by using the terminal ID and thepassword that are included in the login request information receivedthrough the transmitting-receiving section 51 as searching keys, andperforms terminal authentication by determining whether the sameterminal ID and password are managed in the terminal authenticationmanagement DB 5002 (step S23). If the terminal authentication section 52determines that the login request is transmitted from the terminal 10having use authority because the same terminal ID and password aremanaged, the state management section 53 stores the terminal ID, theoperation state, the receiving date of the login request information,and the IP address of the terminal 10 aa in the terminal management DB5003 (refer to FIG. 13) in association with each other (step S24). As aresult, the terminal management table illustrated in FIG. 13 manages theterminal ID “01aa”, the operation state “online”, the receiving date“13:40 on Nov. 10, 2009”, and the IP address “1.2.1.3” of the terminal10 aa in association with each other.

Then, the transmitting-receiving section 51 of the management system 50transmits authentication result information indicating theauthentication result obtained by the terminal authentication section 52to the request origin terminal (terminal 10 aa) that has made the loginrequest through the communications network 2 (step S25). In theembodiment, the following description is made on the case in which therequest origin terminal is determined as the terminal having useauthority by the terminal authentication section 52.

The terminal extraction section 54 of the management system 50 searchesthe destination list management DB 5004 (refer to FIG. 14) by using theterminal ID “01aa” of the request origin terminal (terminal 10 aa) thathas made the login request as a searching key, and reads and extractsthe terminal IDs of the candidates of the destination terminal capableof performing communications with the request origin terminal (terminal10 aa) (step S26). In this case, the terminal IDs (“01ab”, “01ba”, and“01db”) of the destination terminals (terminals 10 ab, 10 ba, and 10 db)corresponding to the terminal ID “01aa” of the request origin terminal(terminal 10 aa) are extracted.

Then, the terminal state extraction section 55 searches the terminalmanagement DB 5003 (refer to FIG. 13) by using the terminal IDs (“01ab”,“01ba”, and “01db”) of the candidates of the destination terminalextracted by the terminal extraction section 54 as searching keys, andreads the operation states (“offline”, “online”, and “online”)corresponding to the respective terminal IDs extracted by the terminalextraction section 54. As a result, the terminal state extractionsection 55 acquires the respective operation states of the terminals (10ab, 10 ba, 10 db) (step S27).

Then, the transmitting-receiving section 51 transmits, to the requestorigin terminal (terminal 10 aa) through the communications network 2,destination state information including the terminal IDs (“01ab”,“01ba”, and “01db”) used as the searching keys at step S27 and therespective operation states (“offline”, “online”, and “online”) of thedestination terminals (terminals 10 ab, 10 ba, and 10 db) correspondingto the respective terminal IDs (step S28). As a result, the requestorigin terminal (terminal 10 aa) can grasp the respective currentoperation states (“offline”, “online”, and “online”) of the terminals(10 ab, 10 ba, and 10 db) that are the candidates of the destinationterminal capable of performing communications with the request originterminal (terminal 10 aa).

Furthermore, the terminal extraction section 54 of the management system50 searches the destination list management DB 5004 (refer to FIG. 14)by using the terminal ID “01aa” of the request origin terminal (terminal10 aa) that has made the login request as a searching key, and extractsthe terminal IDs of the other request origin terminals that register theterminal ID “01aa” of the request origin terminal (terminal 10 aa) asthe candidate of the destination terminal (step S29). In the destinationlist management table illustrated in FIG. 14, the terminal IDs “01ab”,“01ba”, and “01db” of the other request origin terminals are extracted.

Then, the terminal state extraction section 55 of the management system50 searches the terminal management DB 5003 (refer to FIG. 13) by usingthe terminal ID “01aa” of the request origin terminal (terminal 10 aa)that has made the login request as a searching key, and acquires theoperation state of the request origin terminal (terminal 10 aa) that hasmade the login request (step S30).

Then, the transmitting-receiving section 51 transmits the destinationstate information including the terminal ID “01aa” of the request originterminal (terminal 10 aa) and the operation state “online” that areacquired at step S30 to the terminals (10 ba and 10 db) each operationstate of which is “online” in the terminal management DB 5003 (refer toFIG. 13) among the terminals (10 ab, 10 ba, and 10 db) that areidentified with the terminal IDs (“01ab”, “01ba”, and “01db”) extractedat step S29 (steps S31-1 and S31-2). When transmitting the destinationstate information to the terminals (10 ba and 10 db), thetransmitting-receiving section 51 refers to the IP addresses of theterminals managed by the terminal management table illustrated in FIG.13 in accordance with the terminal IDs (“01ba” and “01db”). As a result,the terminal ID “01aa” and the operation state “online” of the requestorigin terminal (terminal 10 aa) that has made the login request can betransmitted to each of the other destination terminals (terminals 10 dband 10 ba) capable of performing communications with the request originterminal (terminal 10 aa) that has made the login request as thedestination.

In each of the other terminals 10, once a user turns ON the power sourceswitch 109 illustrated in FIG. 6, the operation input reception section12 illustrated in FIG. 7 receives the power source ON in the same manneras step S21, and performs the processing in the same manner as steps S22to S31-1 and S31-2. The description thereof is thus omitted.

The processing to select the relaying apparatuses 30 is described belowwith reference to FIG. 21. In FIG. 21, various types of managementinformation are totally transmitted and received by the managementinformation session “sei” illustrated in FIG. 21. In the embodiment, therequest origin terminal (terminal 10 aa) can have a telephoneconversation with at least one of the terminals (10 ba, 10 db) theoperation states of which are online, which are indicated in the stateinformation received at step S31-2, among the terminals 10 serving asthe candidates of the destination. The following description is made onthe case in which a user who uses the request origin terminal (terminal10 aa) selects a start of a telephone conversation with the destinationterminal (terminal 10 db).

Once the user presses the operation button 108 illustrated in FIG. 5 soas to select the terminal 10 db, the operation input reception section12 illustrated in FIG. 7 receives a request for starting a telephoneconversation with the destination terminal (terminal 10 db) (step S41).Then, the transmitting-receiving section 11 of the request originterminal (terminal 10 aa) transmits the start request information thatincludes the terminal ID “01aa” of the terminal 10 aa and the terminalID “01db” of the destination terminal (terminal 10 db) and indicatesthat a telephone conversation is to be started to the management system50 (step S42). As a result, the transmitting-receiving section 51 of themanagement system 50 receives the start request information and cangrasp the IP address “1.2.1.3” of the request origin terminal (terminal10 aa) serving as the transmission origin.

The state management section 53 changes both fields of the operationstate in the records respectively including the terminal IDs “01aa” and“01db” of the terminal management table of the terminal management DB5003 (refer to FIG. 13) to “busy” in accordance with the terminal ID“01aa” of the request origin terminal (terminal 10 aa) and the terminalID “01db” of the destination terminal (terminal 10 db) that are includedin the start request information (step S43). In this case, the requestorigin terminal (terminal 10 aa) and the destination terminal (terminal10 db) are busy and do not start a telephone conversation. If the otherterminals 10 tend to have a telephone conversation with the requestorigin terminal (terminal 10 aa) or the destination terminal (terminal10 db), a notification sound or display that indicates so-called busy isoutput.

The processing to execute the session for selecting the relayingapparatuses 30 is described below. The selection session. ID generationsection 56 a illustrated in FIG. 9 generates the selection session IDused for executing a session for selecting the relaying apparatuses 30(step S44). The session management section 57 stores a selection sessionID “se1” generated at step S44, the terminal ID “01aa” of the requestorigin terminal (terminal 10 aa), and the terminal ID “01db” of thedestination terminal (terminal 10 db) in the session management DB 5005(refer to FIG. 15) of the storage section 5000 and manages them inassociation with each other (step S45).

Then, the primary filtering section 56 of the management system 50illustrated in FIG. 7 performs the primary filtering for the relayingapparatus 30 that relays a telephone conversation between the requestorigin terminal (terminal 10 aa) and the destination terminal (terminal10 db) in accordance with the relaying apparatus management DB 5001, theterminal management DB 5003, and the priority management DB 5006 (stepS46).

The processing performed at step S46 is described in further detailbelow with reference to FIGS. 9 and 22. First, the terminal IP addressextraction section 56 b illustrated in FIG. 9 searches the terminalmanagement DB 5003 (refer to FIG. 13) in accordance with the terminal ID“01aa” of the request origin terminal (terminal 10 aa) and the terminalID “01db” of the destination terminal (terminal 10 db) that are includedin start communications request information transmitted from the requestorigin terminal (terminal 10 aa), and extracts the IP addresses(“1.2.1.3” and “1.3.2.4”) of the terminals (10 aa and 10 db)respectively corresponding to the terminal IDs “01aa” and “01db” (stepS46-1).

Then, the primary selection section 56 c selects the respective relayingapparatus IDs (111 a, 111 b, and 111 d) of the relaying apparatuses (30a, 30 b, and 30 d) the operation states of which are “online” among therelaying apparatuses 30 managed by the relaying apparatus management DB5001 (refer to FIG. 11) (step S46-2). In addition, the primary selectionsection 56 c searches the relaying apparatus management DB 5001 (referto FIG. 11) in accordance with the IP address “1.2.1.3” of the requestorigin terminal (terminal 10 aa) and the IP address “1.3.2.4” of thedestination terminal (terminal 10 db) that are extracted at step S46-1,and investigates whether each dot address of the IP addresses(“1.2.1.2”, “1.2.2.2”, and “1.3.2.2”) of the relaying apparatuses (30 a,30 b, and 30 d) selected at step S46-2 is the same as or different fromeach dot address of the IP addresses (“1.2.1.3” and “1.3.2.4”) of therequest origin terminal (terminal 10 aa) and the destination terminal(terminal 10 db) (step S46-3).

Then, the priority determination section 56 d determines the point ofthe address priority for each of the relaying apparatuses (30 a, 30 b,and 30 d) investigated at step S46-3 with reference to the prioritymanagement DB 5006 (refer to FIG. 16) (step S46-4). The results of thedetermination processing are illustrated in the table of FIG. 23. FIG.23 is a schematic illustrating the calculation of the points ofpriorities when the filtering processing to select the relayingapparatuses 30 is performed. FIG. 23 illustrates the point of theaddress priority, the point of the transmission speed priority, and thetotal point for each relaying apparatus ID. The point of the addresspriority is further classified into the point of each relaying apparatus30 with respect to the request origin terminal (terminal 10 aa) and thepoint with respect to the destination terminal (terminal 10 db). Thetotal point is the sum of the higher point in the two points of theaddress priority and the point of transmission speed priority.

In the embodiment, the IP address “1.2.1.2” of the relaying apparatus 30a is expressed as “same.same.same.different” with respect to the IPaddress “1.2.1.3” of the request origin terminal (terminal 10 aa). As aresult, the point of the address priority is “5” as illustrated in FIG.23. As illustrated in FIG. 1, the IP address of the relaying apparatus30 a is “1.2.1.2” while the IP address of the destination terminal(terminal 10 db) is “1.3.2.4”. Accordingly, the IP address of therelaying apparatus 30 a is expressed as“same.different.different.different” as illustrated in FIG. 16 withrespect to the IP address of the destination terminal (terminal 10 db).As a result, the point of the address priority is “1” as illustrated inFIG. 23. The IP address “1.2.2.2” of the relaying apparatus 30 b isexpressed as “same.same.different.different” with respect to the IPaddress “1.2.1.3” of the request origin terminal (terminal 10 aa). As aresult, the point of the address priority is “3”. The IP address“1.2.2.2” of the relaying apparatus 30 b is expressed as“same.different.same.different” with respect to the IP address “1.3.2.4”of the destination terminal (terminal 10 db). As a result, the point ofthe address priority is “1”. The IP address “1.3.2.2” of the relayingapparatus 30 d is expressed as “same.different.different.different” withrespect to the IP address “1.2.1.3” of the request origin terminal(terminal 10 aa). As a result, the point of the address priority is “1”.The IP address “1.3.2.2” of the relaying apparatus 30 d is expressed as“same.same.same.different” with respect to the IP address “1.3.2.4” ofthe destination terminal (terminal 10 db). As a result, the point of theaddress priority is “5”.

Referring back to FIG. 22, the priority determination section 56 dsearches the priority management DB 5006 (refer to FIG. 17) inaccordance with the maximum data transmission speed of each relayingapparatus 30 managed by the relaying apparatus management DB 5001 (referto FIG. 11), and determines the point of the transmission speed priorityfor each of the relaying apparatuses (30 a, 30 b, and 30 d) selected bythe primary filtering processing performed at step S46-2 (step S46-5).In the embodiment, the maximum data transmission speed of the relayingapparatus 30 a is 100 (Mbps) as illustrated in FIG. 11. Accordingly, thepoint of the transmission speed priority is determined as 3 withreference to the transmission speed priority illustrated in FIG. 17.Likewise, the maximum data transmission speed of the relaying apparatus30 b is calculated as 1000 (Mbps). Accordingly, the point of thetransmission speed priority is determined as 5. Likewise, the maximumdata transmission speed of the relaying apparatus 30 d is calculated as10 (Mbps). Accordingly, the point of transmission speed priority isdetermined as 1.

Then, the primary selection section 56 c selects two relayingapparatuses 30 having the top two total high points among the relayingapparatuses (30 a, 30 b, and 30 d) each of which has the total pointthat is the sum of the point of the transmission speed priority and thehigher point in the address priority, which is the point with respect toeither one of the terminals (10 aa and 10 db) (step S46-6). In theembodiment, the total points of the respective relaying apparatus IDs(111 a, 111 b, and 111 d) are “8”, “8”, and “6” as illustrated in FIG.23. Accordingly, the relaying apparatus 30 a having the relaying ID“111a” and the relaying apparatus 30 b having the relaying apparatus ID“111b” are selected.

After the filtering processing at step S46 is complete, thetransmitting-receiving section 51 illustrated in FIG. 7 transmitsrelaying apparatus filtering information for transferring the number ofrelaying apparatuses 30 selected as described above to the destinationterminal (terminal 10 db) through the communications network 2 (stepS47). The relaying apparatus filtering information includes the numberof relaying apparatuses 30 selected at step S46, which is “2”, theterminal ID “01aa” of the request origin terminal (terminal 10 aa), andthe selection session ID “se1”. As a result, the terminal 10 db cangrasp the number of relaying apparatuses 30 and from which terminal 10 arequest for starting a telephone conversation is made in the executionof the session performed by using the selection session ID “se1”, andthe IP address “1.1.1.2” of the management system 50 serving as thetransmission origin of the relaying apparatus filtering information.

Then, the terminal 10 db transmits receiving completion informationindicating the completion of the receiving of the relaying apparatusfiltering information to the management system 50 from thetransmitting-receiving section 11 through the communications network 2(step S48). The receiving completion information includes the session ID“se1”. As a result, the management system 50 can grasp that the transferof the number of relaying apparatuses in the session executed by usingthe session ID “se1” is complete and the IP address “1.3.2.4” of thedestination terminal (terminal 10 db) serving as the transmissionorigin.

Processing in which the destination terminal (terminal 10 db) selectsthe relaying apparatus 30 is described below with reference to FIGS. 24and 25. In FIG. 24, various types of management information are totallytransmitted and received by the management information session “sei”illustrated in FIG. 2.

The management system 50 transmits prior relay request informationindicating that a relay request is to be made preliminarily, to each ofthe relaying apparatuses (30 a and 30 b) selected at step S46 prior tostarting a telephone conversation in a television conference (stepsS61-1 and S61-2). The prior relay request information includes thesession ID “se1”, the IP address “1.2.1.3” of the request originterminal (terminal 10 aa), and the IP address “1.3.2.4” of thedestination terminal (terminal 10 db). As a result, each of the relayingapparatuses (30 a and 30 b) can grasp that which selection session isused, which terminal is the request origin terminal, and which terminalis the destination terminal, and the IP address “1.1.1.2” of themanagement system 50 serving as the transmission origin of the priorrelay request information.

Then, each of the relaying apparatuses (30 a and 30 b) transmits priortransmission request information indicating that the request originterminal (terminal 10 aa) is requested to transmit the priortransmission information including ping (Packet Internet Groper), whichis described later, to each of the relaying apparatuses (30 a and 30 b)themselves before the start of a telephone conversation with the requestorigin terminal grasped at steps S61-1 and S61-2 from thetransmitting-receiving section 31 through the communications network 2(steps S62-1 and S62-2). The prior transmission information includes thesession ID “se1”. As a result, the request origin terminal (terminal 10aa) can grasp the transmission of the prior transmission requestinformation to each of the relaying apparatuses (30 a and 30 b) and therespective IP addresses (“1.2.1.2” and “1.2.2.2”) of the relayingapparatuses (30 a and 30 b) each serving as the transmission origin ofthe prior transmission request information, in the selection processingof the relaying apparatus 30 executed by using the session ID “se1”.

In this way, the IP address of the destination terminal is not notifiedto the request origin terminal directly from the management system 50while the IP address of the destination terminal is notified to therelaying apparatus 30 a as described at step S61-1 and the relayingapparatus 30 a requests the request origin terminal to transmit theprior transmission request information to the relaying apparatus itself(relaying apparatus 30 a). This is because the notification of no IPaddresses of the other terminals 10 to each terminal 10 securessecurity.

Then, the request origin terminal (terminal 10 aa) transmits the priortransmission information to each of the relaying apparatuses (30 a and30 b) from the transmitting-receiving section 11 through thecommunications network 2 (steps S63-1 and S63-2). The prior transmissioninformation is transmitted to the destination terminal (the terminal 10db) via respective relaying apparatuses (30 a and 30 b), instead of andprior to transmitting the image data and the voice data. This is formeasuring a necessary time period from a time when the request originterminal (terminal 10 aa) transmits the information to a time when thedestination terminal (terminal 10 db) receives the information. Theprior transmission information includes the ping to confirm that therequest origin terminal (terminal 10 aa), the relaying apparatuses (30 aand 30 b), and the destination terminal (terminal 10 db) are connectedso as to enable communications therebetween, a transmission date atwhich the prior transmission information has been transmitted from therequest origin terminal (terminal 10 aa), and the session ID “se1”. As aresult, each of the relaying apparatuses (30 a and 30 b) can grasp thatthe prior transmission information has been transmitted in the executionof the session using the selection session ID “se1” and the IP address“1.2.1.3” of the request origin terminal (terminal 10 aa) serving as thetransmission origin of the prior transmission information.

Then, each of the relaying apparatuses (30 a and 30 b) relays the priortransmission information to the IP address “1.3.2.4” of the destinationterminal (terminal 10 db) included in the prior relay requestinformation received at steps S61-1 and S61-2 (steps S64-1 and S64-2).As a result, the destination terminal (terminal 10 db) can grasp thatthe prior transmission information has been transmitted in the executionof the session using the selection session ID “se1” and the IP addresses(“1.2.1.2” and “1.2.2.2”) of the relaying apparatuses (30 a and 30 b)serving as the transmission origin (relaying origin) of the priortransmission information.

Then, the final filtering section 16 of the destination terminal(terminal 10 db) finally selects the relaying apparatus 30 that relaysimage data and voice data in telephone conversations in the telephoneconference in accordance with the prior transmission information (stepS65).

The processing performed at step S65 is described in further detailbelow with reference to FIGS. 8 and 25. First, the measurement section16 a of the final filtering section 16 illustrated in FIG. 8 measuresthe receiving date at which the transmitting-receiving section 11 of theterminal 10 db received the prior transmission information for eachprior transmission information relayed by the relaying apparatuses (30 aand 30 b) (step S65-1). Then, the calculation section 16 b calculatesthe necessary time period from a time when the prior transmissioninformation is transmitted to a time when the prior transmissioninformation is received in accordance with the difference between theaforementioned receiving date and the transmission date which isincluded in the prior transmission information, for each priortransmission information the receiving time of which has been measured(step S65-2). Then, the final selection section 16 c determines whetherall of the pieces of prior transmission information corresponding to thenumber of relaying apparatuses 30 to be used for relaying, which is “2”,are received in the execution of the session using the session ID “se1”(step S65-3). If all of the pieces of prior transmission information arenot received (NO), the final selection section 16 c determines whether apredetermined period of time (in this case, one minute) elapses fromwhen the terminal 10 db received the prior transmission information(step S65-4). If the predetermined period of time does not elapse (NO),the processing returns to step S65-1. On the other hand, if all of thepieces of prior transmission information are received (YES at stepS65-3), or if the predetermined period of time elapses (YES at stepS65-4), the final selection section 16 c selects the relaying apparatus30 that relayed the prior transmission information that had taken theshortest necessary period of time among the necessary periods of timecalculated by the calculation section 16 b (step S65-5). In theembodiment, the relaying apparatus 30 a is selected as an example on theassumption that the necessary period of time from transmitting toreceiving of the prior transmission information relayed by the relayingapparatus 30 a is shorter than that of the prior transmissioninformation relayed by the relaying apparatus 30 b.

Then, the destination terminal (terminal 10 db) transmits selectioninformation indicating that the relaying apparatus 30 a has beenselected to the management system 50 from the transmitting-receivingsection 11 through the communications network 2 (step S66). Theselection information includes the session ID “se1” and the relayingapparatus ID “111a” of the selected relaying apparatus 30 a. As aresult, the management system 50 can grasp that the relaying apparatus30 a has been selected in the execution of the session using the sessionID “se1”, and the IP address “1.3.2.4” of the destination terminal(terminal 10 db) serving as the transmission origin of the selectioninformation.

Then, the session management section 57 of the management system 50stores the relaying apparatus ID “111a” of the finally selected relayingapparatus 30 a in a field of the relaying apparatus ID of a recordincluding the session ID “se1” in the session management table of thesession management DB 5005 (refer to FIG. 15) and manages it (step S67).Then, the transmitting-receiving section 51 of the management system 50transmits relay start request information indicating a request forstarting a relay to the relaying apparatus 30 a through thecommunications network 2 (step S68). The relay start request informationincludes the respective IP addresses (“1.2.1.3” and “1.3.2.4”) of therequest origin terminal (terminal 10 aa) and the destination terminal(terminal 10 db) that are the relay destinations. As a result, therelaying apparatus 30 a can grasp that the relaying apparatus 30 aitself has been selected and establish a session for transmitting threepieces of image data of low resolution, medium resolution, and highresolution and voice data between the terminals (10 aa and 10 db) (stepS69). Accordingly, the terminals (10 aa and 10 db) can start a telephoneconversation in a television conference.

Incidentally, at the step S47, the management system 50 transmits therelay apparatus filtering information to the destination terminal(terminal 10 db), so that the selecting process is performed at thedestination terminal (terminal 10 db) side (step S65) through the stepsS48 to S64-1 and S64-2. The process is not limited to this. For example,at the step S47, the management system 50 may transmit the relayapparatus filtering information to the request origin terminal (terminal10 aa), so that the request origin terminal (terminal 10 aa) is switchedwith the destination terminal (terminal 10 db) in transmitting andreceiving the various types of information until the steps S64-1 andS64-2. As a result, the request origin terminal (terminal 10 aa) canperform the selection processing of the relaying apparatus instead ofthe processing at step S65 and transmit the selection informationinstead of the processing at step S66.

Processing is described below with reference to FIGS. 26 to 28, which isperformed after a communications control message is created andtransmitted to each terminal 10 and before each terminal 10 executesprocessing in accordance with the communications control message when atelevision conference is held at multiple sites (terminals 10). FIG. 26illustrates a case in which a television conference is held among threeterminals 10 aa, 10 ba, and 10 db. FIG. 26 is a sequence diagramillustrating processing to create, transmit and receive thecommunications control message. FIG. 27 is a flowchart illustratingprocessing to mainly create the communications control message. FIG. 28is a flowchart illustrating a part of processing to create thecommunications control message in detail. In the embodiment, a case isdescribed in which a conference is held among the three terminals (10aa, 10 ba, 10 db) serving as the multiple sites.

As illustrated in FIG. 26, the message creation section 20 of eachterminal 10 (in this case, the terminal 10 aa) reads the preliminarilystored image communications state information from the storage section1000 and creates the image communications state message (m) includingthe image communications state information (step S71). The imagecommunications state message (m) includes the IP address “1.2.1.3” ofthe terminal 10 aa. The image communications state message (m) mayinclude the destination name instead of the IP address. The imagecommunications state message (m) can be created in a XML (eXtensibleMarkup Language) format according to XMPP (eXtensible Messaging andPresence Protocol) of RFC3921, for example. The communications controlmessage and a display control message, which are described later, can bealso created in the same format.

Then, the transmitting-receiving section 11 of the terminal 10 aatransmits the image communications state message (m) created at step S71to the management system 50 through the communications network 2 (stepS72). As a result, the transmitting-receiving section 51 of themanagement system 50 receives the image communications state message(m).

Then, the message creation section 61 of the management system 50creates communications control messages in accordance with the imagecommunications states of the respective terminals 30 (step S73). StepS73 is described in detail with reference to FIG. 27.

The message creation section 61 acquires the image communications stateinformation relating to the terminal 10 aa serving as the transmissionorigin and the IP address “1.2.1.3” of the terminal 10 aa from the imagecommunications state message (m) received by the transmitting-receivingsection 51 (step S73-1). Then, the message creation section 61 rewritesthe attribute of the image communications state corresponding to the IPaddress acquired at step S73-1 in the terminal management DB 5003 (referto FIG. 13) by overwriting it with the image communications stateinformation acquired at step S73-1 (step S73-2).

Then, the message creation section 61 extracts the terminal IDcorresponding to the IP address acquired at step S73-1 from the terminalmanagement DB 5003 (refer to FIG. 13) (step S73-3).

Then, the terminal extraction section 54 searches the destination listmanagement DB 5004 by using the terminal ID extracted at step S73-3 asthe terminal ID of the request origin terminal, and extracts all of theterminal IDs of the destination terminals corresponding to the extractedterminal ID (step S73-4). The terminal state extraction section 55searches the terminal management DB 5003 (refer to FIG. 13) inaccordance with the terminal IDs of the destination terminals andextracts the image communications state information corresponding toeach of the terminal IDs (step S73-5).

Then, the message creation section 61 determines whether each of therequest origin terminal and all of the destination terminals has theimage communications function with, reference to the imagecommunications state information extracted at step S73-5 (step S73-6).If the request origin terminal and all of the destination terminals hasno image communications function (NO), the processing at step S73 ends.In this case, message transmission processing (refer to FIGS. 26 and 27)performed at step S74, which is described later, is not performed.

On the other hand, if the request origin terminal and any of all of thedestination terminals have the image communications function (YES), themessage creation section 61 creates the communications control message,which is described later, in accordance with the image communicationsstate of each terminal 10 (step S73-7).

Step S73-7 is described in detail below with reference to FIG. 28. Themessage creation section 61 determines whether two or more terminals 10are performing image communications among the terminals (10 aa, 10 ba,and 10 db) in telephone conversations made among the multiple sites withreference to the image communications states extracted at step S73-5(step S101). If it is determined that the terminals 10 are performingimage communications (YES at step S101), the message creation section 61further determines whether the terminal 10 that is halting imagecommunications is included in the remaining terminals 10 (step S102). Ifit is determined that the terminal 10 that is halting image,communications is included (YES at step S102), the terminal stateextraction section 55 extracts the IP address of the terminal 10 that ishalting image communications and for which it is determined that it isincluded at step S102 with reference to the terminal management DB 5003(refer to FIG. 13) (step S103). The message creation section 61 createsa communications control message (M3) indicating that the terminals areperforming image communications (step S104). Specifically, thecommunications control message (M3) includes a message“MESSAGE_IMAGE_ON”, the IP address of the transmission destinationextracted at step S103, and the IP address of the management system 50serving as the transmission origin.

On the other hand, if it is determined that the terminals 10 are notperforming image communications (NO at step S101), the message creationsection 61 determines whether only a single terminal 10 is performingimage communications with reference to the image communications statesextracted at step S73-5 (step S105). If it is determined that only asingle terminal 10 is performing image communications (YES at stepS105), the message creation section 61 further determines whether all ofthe other terminals 10 excluding the terminal 10 that is performing theimage communications have no image communications function withreference to the image communications states extracted at step S73-5(step S106). If it is determined that all of the other the terminals 10excluding the terminal 10 in the image communications have no imagecommunications functions (YES at step S106), the terminal stateextraction section 55 extracts the IP address of the single terminal 10for which it is determined that it is performing image communications atstep S105 with reference to the terminal management DB 5003 (refer toFIG. 13) (step S107). The message creation section 61 creates acommunications control message (M4) indicating that the imagecommunications is forcibly stopped (step S108). Specifically, thecommunications control message (M4) includes a message “DATA_IMAGE_OFF”,the IP address of the transmission destination extracted at step S107,and the IP address of the management system 50 serving as thetransmission origin.

On the other hand, if it is not determined that all of the terminals 10excluding the terminal 10 that is performing the image communicationshave no image communications functions (NO at step S106), i.e., it isdetermined that at least one of the terminals 10 excluding the terminal10 that is performing the image communications has the imagecommunications function, the message creation section 61 furtherdetermines whether the terminal 10 that is halting image communicationsis included in the terminals 10 having the image communicationsfunctions with reference to the image communications states extracted atstep S73-5 (step S109). If it is determined that the terminal 10 that ishalting image communications is included (YES at step S109), theterminal state extraction section 55 extracts the IP address of theterminal 10 that is performing image communications and for which it isdetermined that it is included at step S105 with reference to theterminal management DB 5003 (refer to FIG. 13) (step S110). The messagecreation section 61 creates a communications control message (M1)indicating that the terminals are halting image communications (stepS111). Specifically, the communications control message (M1) includesthe message “MESSAGE_IMAGE_OFF”, the IP address of the transmissiondestination extracted at step S110, and the IP address of the managementsystem 50 serving as the transmission origin.

The terminal state extraction section 55 further extracts the IP addressof the terminal 10 that is halting image communications and for which itis determined that it is included at step S109 with reference to theterminal management DB 5003 (refer to FIG. 13) (step S112). The messagecreation section 61 creates a communications control message (M2)indicating that the other single terminal is performing imagecommunications (step S113). Specifically, the communications controlmessage (M2) includes the message “MESSAGE_IMAGE_ON”, the IP address ofthe transmission destination extracted at step S112, and the IP addressof the management system 50 serving as the transmission origin.

On the other hand, the terminal state extraction section 55 extracts theIP address of the terminal 10 for which it is determined that it has theimage communications function at step S73-6 with reference to theterminal management DB 5003 (refer to FIG. 13) in any one of thefollowing cases: (1) if it is not determined that the terminal 10 thatis halting image communications is included in the remaining terminals10 (NO at step S102), (2) if it is not determined that only the singleterminal 10 is performing image communications (NO at step S105), i.e.,no terminal 10 is performing image communications, and (3) it is notdetermined that the terminal 10 that is halting image communications isincluded (NO at step S109) (step S114). The message creation section 61creates a display control message (M5) indicating that a specifieddisplay message displayed on each display 120 of the terminals 10 is tobe deleted (step S115). Specifically, the display control message (M5)includes the message “MESSAGE_IMAGE_ON”, the IP address of thetransmission destination extracted at step S114, and the IP address ofthe management system 50 serving as the transmission origin.

In this way, the message creation section 61 creates the communicationscontrol message (M1, M2, M3, or M4) or the display control message (M5).

Then, the transmitting-receiving section 51 of the management system 50transmits, to the three terminals (10 aa, 10 ba, and 10 db) serving asthe multiple sites through the communications network 2, thecommunications control message (M1, M2, M3, or M4) or the displaycontrol message (M5), which is created in accordance with the imagecommunications state of each terminal serving as the transmission sideor the receiving side in telephone conversations made among theterminals (step S74). In FIG. 26, step S74-1 illustrates thetransmission from the management system 50 to the terminal ba, stepS74-2 illustrates the transmission from the management system 50 to theterminal db, and S74-3 illustrates the transmission from the managementsystem 50 to the terminal aa. Steps S74-1, S74-2, and S74-3 are includedin step S74.

Specifically, when step S103 is executed, the transmitting-receivingsection 51 of the management system 50 transmits the communicationscontrol message (M3) created at step S104 to the IP address extracted atstep S103. When step S107 is executed, the transmitting-receivingsection 51 transmits the communications control message (M4) created atstep S108 to the IP address extracted at step S107. When step S110 isexecuted, the transmitting-receiving section 51 transmits thecommunications control message (M1) created at step S111 to the IPaddress extracted at step S110. When step S112 is executed, thetransmitting-receiving section 51 transmits the communications controlmessage (M2) created at step S113 to the IP address extracted at stepS112. When step S114 is executed, the transmitting-receiving section 51transmits the communications control message (M5) created at step S115to the IP address extracted at step S114.

As a result, each of the terminals (10 aa, 10 ba, and 10 db) performsprocessing in accordance with the content of the communications controlmessage (M1, M2, M3, or M4) or the display control message (M5) (stepsS75-1 to S75-3).

Processing performed at steps S75-1 to S75-3 is described below withreference to FIGS. 29 to 32. FIGS. 29 to 32 are schematics illustratingexamples of a television conference screen displayed on the display 120of the terminal 10. A television conference screen P1 displayed on thedisplay 120 includes a main screen P2, and sub screens P3 and P4. Thetelevision conference screen P1 further includes two sub screens locatedunder the sub screen P4 and three sub screens located on the left sideof the sub screen located at the lowest position from the sub screen P4.At the bottom of the television conference screen P1, displayed are amessage display area P5 in which a display message is displayed, a“screen switching” button P6 that is pressed by a mouse pointer, forexample, when images displayed on the main screen and the sub screensare switched, and a camera icon P7 that indicates whether the powersource of the camera 112 of the terminal 10 itself is turned on and theterminal 10 performs image communications, or whether the power sourceof the camera 112 of the terminal 10 itself is turned off and theterminal 10 does not perform image communications. The display of “x” onthe camera icon P7 means that the power source of the camera 112 of theterminal 10 itself is on and a user will be able to turn off the powersource. On the other hand, no display of “x” on the camera icon P7 meansthat the power source of the camera 112 of the terminal 10 itself is offand a user will be able to turn on the power source.

When the communications control message (M3) indicating that the otherterminals are performing image communications is created at step S104,the display control section 17 of the terminal 10 causes the display 120to display a display message, e.g., “Images are being received from theother site and the camera of this terminal is off” in the messagedisplay area P5 as illustrated in FIG. 29. The main screen P2 displaysan image of the other party as a main display and the sub screen P3originally displays an image of the own terminal. In this case, no imageis displayed on the sub screen P3. However, the sub screen P4 displaysthe image of the other party as a sub display.

As a result, a user can recognize the state in which the own terminal istransmitting no image data and image data is being transmitted from theother terminal by viewing the television conference screen P1illustrated in FIG. 29. If a user wants to transmit image date from theown terminal, the user can start transmitting the image data by pressingthe camera icon P7. Once the camera icon P7 is pressed, the camera iconP7 displays “x” thereon.

When the communications control message (M4) indicating that imagecommunications is to be forcibly stopped is created at step S108, theimage capturing section 14 of the terminal 10 stops imaging and thetransmitting-receiving section 11 stops transmitting the image data(stops image communications) on a command from the CPU 101. The displaycontrol section 17 causes the display 120 to hide displays on all of thescreens P2, P3, P4, and so on of the television conference screen P1 andto delete “x” from the camera icon P7 as illustrated in FIG. 30. Theimage capturing section 14 includes the camera 112 illustrated in FIG. 5and an external camera connected to the external device connection I/F.

As a result, a user can recognize the state in which the own terminal istransmitting no image data, the camera 112 of the own terminal ishalting imaging, and no image data is being transmitted from the otherterminal by viewing the television conference screen P1 illustrated inFIG. 30.

When the communications control message (M1) indicating that all of theother terminals are halting image communications is created at stepS111, the display control section 17 of the terminal 10 causes thedisplay 120 to display a display message, e.g., “No images are beingreceived from the other sites and the camera of this terminal is on” inthe message display area P5 as illustrated in FIG. 31. In FIG. 31,nothing is displayed on the main screen P2 and the sub screen P4, andthe image of the own terminal is displayed on the sub screen P3.

As a result, a user can recognize the state in which only the ownterminal is transmitting image data and no image data is beingtransmitted from all of the other terminals by viewing the televisionconference screen P1 illustrated in FIG. 31.

When the communications control message (M2) indicating that the othersingle terminal is performing image communications is created at stepS113, the display control section 17 of the terminal 10 causes thedisplay 120 to display a display message, e.g., “images are beingreceived from one of the sites and the camera of this terminal is off”in the message display area P5 as illustrated in FIG. 32. In FIG. 32, animage of the other party at the site is displayed on the main screen P2,and nothing is displayed on the sub screens P3 and P4.

As a result, a user can recognize the state in which the own terminal istransmitting no image data and image data is being transmitted from onlyone of the other terminals at the other parties by viewing thetelevision conference screen P1 illustrated in FIG. 32.

When the image of FIG. 31 is displayed by the terminal 10 on one sideand the image of FIG. 32 is displayed by another terminal 10 on theother side in this way, each user of the terminals 10 can select whetherto perform image communications therebetween in accordance with bothimage communications states.

When the communications control message (M5) indicating that the displaymessage is to be deleted is created at step S115, the display controlsection 17 of the terminal 10 deletes the display message displayed inthe message display area P5.

The terminal 10 having the image communications function can transmitthe image communications message not only by the processing performed atstep S72 of FIG. 26 but also when the camera icon P7 is pressed during atelevision conference. Specifically, when a user presses the camera iconP7 in a state indicating “x” as illustrated in FIG. 31 so that thecamera icon P7 becomes a state as illustrated in FIG. 29, the messagecreation section 20 of the terminal 10 creates the image communicationsstate message indicating that the terminal 10 is halting imagecommunications. When a user presses the camera icon P7 in a state asillustrated in FIG. 29 so that the camera icon P7 becomes a stateindicating “x” as illustrated in FIG. 31, the message creation section20 of the terminal 10 creates the image communications state messageindicating that the terminal 10 is performing image communications.

Processing to transmit and receive image data and voice data fortelephone conversations in a television conference between the requestorigin terminal and the destination terminal is described below withreference to FIGS. 7 and 33. The transmitting and receiving the imagedata and the voice data and detection of the delay time, which isdescribed later, are processed in the same manner both in the processingfor transmitting the image data and the voice data from the terminal 10aa to the terminal 10 db in one direction and in the processing fortransmitting the image data and the voice data from the terminal 10 dbto the terminal 10 aa in the opposite direction. Therefore,communications in the one direction is described while thecommunications in the opposite direction is omitted.

The request origin terminal (terminal 10 aa) transmits image data of asubject imaged by an image capturing section 14 a, and voice data of avoice received by the voice input section 15 a to the relaying apparatus30 a from the transmitting-receiving section 11 through thecommunications network 2 by the image/voice data session “sed”illustrated in FIG. 2 (step S81). In the embodiment, high image qualityimage data including three pieces of image data of low resolution,medium resolution, and high resolution illustrated in FIGS. 3A to 3C andvoice data are transmitted. As a result, in the relaying apparatus 30 a,the transmitting-receiving section 31 receives the image data composedof three pieces of different resolution image data and the voice data.The data quality confirmation section 33 searches the quality changemanagement DB 3001 (refer to FIG. 10) by using the IP address “1.3.2.4”of the destination terminal (terminal 10 db) as a searching key,extracts the image quality, which corresponds to the IP address, of theimage data to be relayed, and confirms the image quality of the imagedata to be relayed (step S82). In the embodiment, the confirmed imagequality of the image data is “high image quality”, which is the same asthat of the image data received by the transmitting-receiving section31. Accordingly, the relaying apparatus 30 a transmits the image dataand the voice data to the destination terminal (terminal 10 db) withoutany change by the image/voice data session sed (step S83). As a result,the transmitting-receiving section 11 of the destination terminal(terminal 10 db) receives the high image quality image data composed ofthree pieces of image data of low resolution, medium resolution, andhigh resolution and the voice data. The display control section 17 cancombine the three pieces of image data having different resolutions,cause the display 120 to display the resulting image, and cause thevoice output section 15 b to output a voice based on the voice data.

Then, the delay detection section 18 of the terminal 10 db detects thedelay time in receiving of image data received by thetransmitting-receiving section 11 at a regular time intervals (e.g.,every one second) (step S84). In the embodiment, the followingdescription is made on a case in which the delay time is 200 (ms).

The transmitting-receiving section 11 of the destination terminal(terminal 10 db) transmits the delay information indicating the delaytime “200 (ms)” to the management system 50 through the communicationsnetwork 2 by the management information session “sei” illustrated inFIG. 2 (step S85). As a result, the management system 50 can grasp thedelay time and the IP address “1.3.2.4” of the terminal 10 db serving asthe transmission origin of the delay information.

Then, the delay time management section 60 of the management system 50searches the terminal management DB 5003 (refer to FIG. 13) by using theIP address “1.3.2.4” of the destination terminal (terminal 10 db) as asearching key, and extracts the terminal ID “01db” corresponding to theIP address. In addition, the delay time management section 60 stores thedelay time “200 (ms)” indicated by the delay information in the field ofthe delay time of the record of the terminal ID “01db” in the sessionmanagement table of the session management DB 5005 (refer to FIG. 15)and manages it (step S86).

Then, the quality determination section 58 searches the qualitymanagement DB 5007 (refer to FIG. 18) by using the delay time “200 (ms)”as a searching key, extracts the image quality “medium image quality” ofthe image data corresponding to the delay time, and determines the imagequality as the “medium image quality” (step S87).

Then, the transmitting-receiving section 51 searches the relayingapparatus management DB 5001 (refer to FIG. 11) by using the relayingapparatus ID “111a” associated with the terminal ID “01db” in thesession management table of the session management DB (refer to FIG. 15)as a searching key, and extracts the IP address “1.2.1.2” of therelaying apparatus 30 a corresponding to the relaying apparatus ID (stepS88). The transmitting-receiving section 51 transmits the qualityinformation indicating the image quality “medium image quality” of theimage data determined at step S87 to the relaying apparatus 30 a throughthe communications network 2 by the management information session seiillustrated in FIG. 2 (step S89). The quality information includes theIP address “1.3.2.4” of the destination terminal (terminal 10 db) usedas the searching key at step S86. As a result, the quality changemanagement section 34 of the relaying apparatus 30 a stores the IPaddress “1.3.2.4” of the terminal 10 serving as the transmissiondestination (in this case, the terminal 10 db) and the image quality“medium image quality” of the image data to be relayed in the qualitychange management DB 3001 (refer to FIG. 10) and manages them inassociation with each other (step S90).

Then, the terminal 10 aa transmits the high image quality image datacomposed of three pieces of image data of low resolution, mediumresolution, and high resolution and the voice data to the relayingapparatus 30 a by the image/voice data session “sed” in the same manneras step S81 (step S91). As a result, the data quality confirmationsection 33 of the relaying apparatus 30 a searches the quality changemanagement DB 3001 (refer to FIG. 10) by using the IP address “1.3.2.4”of the destination terminal (terminal 10 db) as a searching key,extracts the image quality “medium image quality”, which corresponds tothe IP address, of the image data to be relayed, and confirms the imagequality of the image data to be relayed in the same manner as step S82(step S92). In the embodiment, the confirmed image quality of the imagedata is “medium image quality”, which is lower than the image quality“high image quality” of the image data received by thetransmitting-receiving section 31. Therefore, the data quality changesection 35 changes the image quality of the image data by suppressingthe image quality of the image data from “high image quality” to “mediumimage quality” (step S93).

Then, the transmitting-receiving section 31 transmits the image data theimage quality of which has been changed to “medium image quality” andthe voice data the sound quality of which has not been changed to theterminal 10 db through the communications network 2 by the image/voicedata session sed (step S94). As a result, the transmitting-receivingsection 11 of the destination terminal (terminal 10 db) receives themedium image quality image data composed of two pieces of image data oflow resolution and medium resolution, and the voice data. Then, thedisplay control section 17 can combine the two pieces of image datahaving different resolutions, cause the display 120 to display theresulting image, and cause the voice output section 15 b to output avoice based on the voice data.

In this way, when delay in receiving occurs in the destination terminal(terminal 10 db) that receives image data, the relaying apparatus 30 achanges the image quality such that persons who are attending in atelevision conference feel no strangeness in the image.

<<Major Effect of Embodiment>>

As described above, in the embodiment, the management system 50 createsthe specified communications control message for causing the specifiedterminal 10 to control image communications in accordance with thepieces of image communications state information indicating the imagecommunications states of the terminals 10, and transmits thecommunications control message to the terminal 10 that is caused tocontrol the image communications. Accordingly, the transmissionmanagement system can cause the specified transmission terminal toperform image communications in accordance with the image communicationsstate of the terminal 10 on the other parties' side. As a result, thetransmission management system can prevent unnecessary imagecommunications. In addition, unnecessary power consumption andcommunications costs are eliminated.

It is difficult to grasp the environment of the whole of the Internet 2i while the environment of the LAN2 such as the IP address of therelaying apparatus 30 can be grasped in the communications network 2.Therefore, at first, two or more relaying apparatuses 30 are selectedamong the relaying apparatuses 30 that relay image data and voice datain accordance with information of a graspable environment. Then, theprior transmission information is transmitted and received between theterminals 10 instead of image data and voice data before the image dataand voice data are practically transmitted and received. As a result,the relaying apparatus 30 that can actually relay the prior transmissioninformation with the shortest period of time can be selected.

That is, two or more relaying apparatuses 30 having the top two or moreIP addresses similar to any of the IP addresses of the terminals 10 areselected. As a result, two or more candidates of the relaying apparatus30 finally to be used can remain. Thereafter, the prior transmissioninformation is practically transmitted and received between the requestorigin terminal and the destination terminal through each of therelaying apparatuses 30 serving as the candidates. As a result, therelaying apparatus 30 that has relayed the prior transmissioninformation with the shortest necessary period of time for transmittingand receiving can be selected among two or more relaying apparatuses 30serving as the candidates. Consequently, the highest quality image dataor voice data under the environment of the current communicationsnetwork 2 can be transmitted and received.

In the embodiment, two or more relaying apparatuses 30 are selected notonly by preferentially selecting the relaying apparatus 30 having the IPaddress similar to any of the IP addresses of the terminals 10performing a television conference but also taking the maximum datatransmission speed of each relaying apparatus 30 into consideration. Asa result, the candidates of the relaying apparatus 30 can be selectedthat fit the actual environment of the communications network 2.

In the embodiment, the relaying apparatuses 30 are selected among therelaying apparatuses 30 in online. As a result, the candidates of therelaying apparatus 30 can be selected that fit the actual environment ofthe communications network 2.

[Supplemental Explanation of Embodiment]

The relaying apparatus 30, the management system 50, the program supplysystem 90, and the maintenance system 100 in the embodiment may bestructured by a single computer. The sections (functions or means) ofthem may be divided and the divided sections may be structured by aplurality of computers each allocated for any section. When the programsupply system 90 is structured by a single computer, a programtransmitted by the program supply system 90 may be transmitted as aplurality of divided modules or transmitted without being divided. Whenthe program supply system 90 is structured by a plurality of computers,a program may be transmitted from the computers as a plurality ofdivided modules.

The recording medium, such as CD-ROM, in which the terminal program, therelaying apparatus program, and the transmission management program ofthe embodiment are stored, the HD 204 that stores therein the programs,and the program supply system 90 including the HD 204 are used asprogram products when the terminal program, the relaying apparatusprogram, and the transmission management program are provided to a userand the like in domestically or overseas.

As an example of quality of an image represented by image data relayedby the relaying apparatus 30, attention is paid on the resolution of theimage represented by the image data and the resolution is managed by thequality change management table illustrated in FIG. 10 and the qualitymanagement table illustrated in FIG. 18. The image quality is notlimited to the resolution. As other examples of quality, attention maybe paid on depth of image quality of the image represented by the imagedata, a sampling frequency of a voice in voice data, and a bit length ofa voice in voice data and the quality may be managed. Voice data may betransmitted and received by being divided into three pieces of datahaving different resolutions (high resolution, medium resolution, andlow resolution).

In FIGS. 11, 13, and 15, the receiving date is managed. The managementitem is not limited to the receiving date. At least receiving time maybe managed in the receiving date.

In the embodiment, the IP address of the relaying apparatus is managedin FIG. 11 while the IP address of the terminal is managed in FIG. 13.However, the management item is not limited to the IP address. Each FQDN(Fully Qualified Domain Name) of the relaying apparatus and the terminalmay be managed as relay apparatus identification information foridentifying the relaying apparatus 30 on the communications network 2 orterminal identification information for identifying the terminal 10 onthe communications network 2. In this case, the IP address correspondingto the FQDN is acquired by a known DNS (Domain Name System) server. Theexpression of “the relaying apparatus identification information foridentifying the relaying apparatus 30 on the communications network 2”may be also expressed as “the relaying apparatus connection destinationinformation indicating the connection destination to the relayingapparatus 30 on the communications network 2” or “the relaying apparatusdestination information indicating the destination to the relayingapparatus 30 on the communications network 2”. Likewise, the expressionof “the terminal identification information for identifying the terminal10 on the communications network 2” may be also expressed as “theterminal connection destination information indicating the connectiondestination to the terminal 10 on the communications network 2” or “theterminal destination information indicating the destination to theterminal 10 on the communications network 2”.

In the embodiment, the television conference system is described as anexample of the transmission system 1. However, the transmission system 1is not limited to be applied to the television conference system. Thetransmission system 1 may be applicable to a telephone system such as anIP (Internet Protocol) telephone and an Internet telephone. Thetransmission system 1 may be a car navigation system. In this case, theterminal 10 on one side corresponds to a car navigation system mountedon a vehicle while the terminal 10 on the other side corresponds to amanagement server or management terminal of a management center thatmanages the car navigation or another car navigation system mounted onanother vehicle. The transmission system 1 may be a communication systemof cell phones. In this case, the terminal 10 corresponds to the cellphone, for example.

In the embodiment, image data and voice data are described as an exampleof the content data. However, the data is not limited to the image dataand the voice data. Touch data may be applicable. In this case, a senseof touch obtained by a user at a terminal on one side is transmitted toanother terminal on the other side. The content data may be olfaction(smell) data. In this case, an aroma (smell) at a terminal on one sideis transmitted to another terminal on the other side. The content datamay be at least one piece of image data, voice data, touch data, andolfaction data.

In the embodiment, the television conference is held by using thetransmission system 1. However, the transmission system 1 is not limitedto be used for the television conference. The transmission system 1 maybe used for meetings, general conversations among family members orfriends or information supply in one direction.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

The invention claimed is:
 1. A transmission management system thatmanages image communications among a plurality of transmission terminalscapable of performing at least voice communications, the transmissionmanagement system comprising: a terminal management section that managesimage communications state information indicating an imagecommunications state of each of the transmission terminals for eachterminal identification information for identifying each transmissionterminal; a creation section that creates a specified communicationscontrol message causing the specified transmission terminal to controlthe image communications in accordance with the image communicationsstate information; and a transmitting section that transmits the createdcommunications control message to the transmission terminal caused tocontrol the image communications among the transmission terminals. 2.The transmission management system according to claim 1, wherein in afirst case in which the image communications state information indicatesthat a single transmission terminal is performing image communicationsand one or more other transmission terminals are halting imagecommunications among the transmission terminals, the creation sectioncreates a first communications control message indicating that the oneor more other transmission terminals are halting image communicationsand a second communications control message indicating that the singletransmission terminal is performing image communications, and thetransmitting section transmits the first communications control messageto the single transmission terminal that is performing imagecommunications and the second communications control message to the oneor more other transmission terminals that are halting imagecommunications.
 3. The transmission management system according to claim1, wherein in a second case in which the image communications stateinformation indicates that more than one of the transmission terminalsare performing image communications and one or more other transmissionterminals are halting image communications among the transmissionterminals, the creation section creates a third communications controlmessage indicating that the more than one of the transmission terminalsare performing image communications, and the transmitting sectiontransmits the third communications control message to the one or moreother transmission terminals that are halting image communications. 4.The transmission management system according to claim 1, wherein in athird case in which the image communications state information indicatesthat a single transmission terminal is performing image communicationsand one or more other transmission terminals have no imagecommunications function among the transmission terminals, the creationsection creates a fourth communications control message indicating thatthe image communications is to be forcibly stopped, and the transmittingsection transmits the fourth communications control message to thesingle transmission terminal that is performing image communications. 5.The transmission management system according to claim 1, wherein in afourth case in which the image communications state information does notcorrespond to any of a first case in which the image communicationsstate information indicates that a single transmission terminal isperforming image communications and one or more other transmissionterminals are halting image communications among the transmissionterminals, a second case in which the image communications stateinformation indicates that more than one of the transmission terminalsare performing image communications and one or more other transmissionterminals are halting image communications among the transmissionterminals, and a third case in which the image communications stateinformation indicates that a single transmission terminal is performingimage communications and one or more other transmission terminals haveno image communications function among the transmission terminals, thecreation section creates a display control message indicating thatspecified display messages displayed on the transmission terminals areto be deleted, and the transmitting section transmits the displaycontrol message to the transmission terminals.
 6. A transmission system,comprising: the transmission management system according to claim 2; andthe transmission terminals whose image communications are managed by thetransmission management system, wherein each of the transmissionterminals includes: a receiving section that receives a communicationscontrol message transmitted from the transmission management system; anda display control section that causes a specified display section todisplay a display message based on the received communications controlmessage.
 7. A transmission system, comprising: the transmissionmanagement system according to claim 4; and the transmission terminalswhose image communications are managed by the transmission managementsystem, wherein each of the transmission terminals includes: a receivingsection that receives a communications control message transmitted fromthe transmission management system; and a communications stop sectionthat causes the transmission terminal to stop performing imagecommunications in accordance with the received communications controlmessage.
 8. The transmission system according to claim 7, wherein eachof the transmission terminals further includes a control section thatcauses an image capturing section imaging a subject and obtaining imagedata to be subjected to the image communications to stop the imaging inaccordance with the communications control message received by thereceiving section.
 9. A transmission system, comprising: thetransmission management system according to claim 5; and thetransmission terminals whose image communications are managed by thetransmission management system, wherein each of the transmissionterminals includes: a receiving section that receives a display controlmessage transmitted from the transmission management system; and adisplay control section that causes a specified display section todelete the specified display message displayed on the specified displaysection in accordance with the received display control message.
 10. Anon-transitory computer-readable recording medium with an executableprogram stored thereon and executed by a computer of a transmissionmanagement system that manages image communications among a plurality oftransmission terminals capable of performing at least voicecommunications, wherein the program instructs a computer to perform:managing image communications state information indicating an imagecommunications state of each of the transmission terminals for eachterminal identification information for identifying each transmissionterminal; creating a specified communications control message causingthe specified transmission terminal to control the image communicationsin accordance with the image communications state information; andtransmitting the created communications control message to thetransmission terminal caused to control the image communications amongthe transmission terminals.
 11. A program supply system that suppliesthe program stored on the computer-readable recording medium accordingto claim 10 to the transmission management system through acommunications network.
 12. A maintenance system that performsmaintenance of the transmission management system according to claim 1.